diff --git a/cmds/installd/tests/Android.bp b/cmds/installd/tests/Android.bp
index 630c1f3..443dce6 100644
--- a/cmds/installd/tests/Android.bp
+++ b/cmds/installd/tests/Android.bp
@@ -5,13 +5,13 @@
     srcs: ["installd_utils_test.cpp"],
     shared_libs: [
         "libbase",
-        "liblog",
         "libutils",
         "libcutils",
     ],
     static_libs: [
-        "libinstalld",
         "libdiskusage",
+        "libinstalld",
+        "liblog",
     ],
 }
 
@@ -23,14 +23,14 @@
         "libbase",
         "libbinder",
         "libcutils",
-        "liblog",
-        "liblogwrap",
         "libselinux",
         "libutils",
     ],
     static_libs: [
-        "libinstalld",
         "libdiskusage",
+        "libinstalld",
+        "liblog",
+        "liblogwrap",
     ],
 }
 
@@ -42,13 +42,13 @@
         "libbase",
         "libbinder",
         "libcutils",
-        "liblog",
-        "liblogwrap",
         "libselinux",
         "libutils",
     ],
     static_libs: [
-        "libinstalld",
         "libdiskusage",
+        "libinstalld",
+        "liblog",
+        "liblogwrap",
     ],
 }
diff --git a/include/android/sensor.h b/include/android/sensor.h
index a88733c..2db0ee7 100644
--- a/include/android/sensor.h
+++ b/include/android/sensor.h
@@ -197,7 +197,7 @@
  * A sensor event.
  */
 
-/* NOTE: Must match hardware/sensors.h */
+/* NOTE: changes to these structs have to be backward compatible */
 typedef struct ASensorVector {
     union {
         float v[3];
@@ -259,7 +259,7 @@
     };
 } AAdditionalInfoEvent;
 
-/* NOTE: Must match hardware/sensors.h */
+/* NOTE: changes to this struct has to be backward compatible */
 typedef struct ASensorEvent {
     int32_t version; /* sizeof(struct ASensorEvent) */
     int32_t sensor;
diff --git a/include/audiomanager/IPlayer.h b/include/audiomanager/IPlayer.h
deleted file mode 100644
index de5c1c7..0000000
--- a/include/audiomanager/IPlayer.h
+++ /dev/null
@@ -1,69 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef ANDROID_IPLAYER_H
-#define ANDROID_IPLAYER_H
-
-#include <stdint.h>
-#include <sys/types.h>
-
-#include <media/VolumeShaper.h>
-#include <utils/RefBase.h>
-#include <utils/Errors.h>
-#include <binder/IInterface.h>
-
-namespace android {
-
-// ----------------------------------------------------------------------------
-
-class IPlayer : public IInterface
-{
-public:
-    DECLARE_META_INTERFACE(Player);
-
-    virtual void start() = 0;
-
-    virtual void pause() = 0;
-
-    virtual void stop() = 0;
-
-    virtual void setVolume(float vol) = 0;
-
-    virtual void setPan(float pan) = 0;
-
-    virtual void setStartDelayMs(int delayMs) = 0;
-
-    virtual void applyVolumeShaper(
-            const sp<VolumeShaper::Configuration>& configuration,
-            const sp<VolumeShaper::Operation>& operation) = 0;
-};
-
-// ----------------------------------------------------------------------------
-
-class BnPlayer : public BnInterface<IPlayer>
-{
-public:
-    virtual status_t    onTransact( uint32_t code,
-                                    const Parcel& data,
-                                    Parcel* reply,
-                                    uint32_t flags = 0);
-};
-
-// ----------------------------------------------------------------------------
-
-}; // namespace android
-
-#endif // ANDROID_IPLAYER_H
diff --git a/include/input/VelocityTracker.h b/include/input/VelocityTracker.h
index 795f575..ffa1614 100644
--- a/include/input/VelocityTracker.h
+++ b/include/input/VelocityTracker.h
@@ -264,6 +264,40 @@
     Movement mMovements[HISTORY_SIZE];
 };
 
+class ImpulseVelocityTrackerStrategy : public VelocityTrackerStrategy {
+public:
+    ImpulseVelocityTrackerStrategy();
+    virtual ~ImpulseVelocityTrackerStrategy();
+
+    virtual void clear();
+    virtual void clearPointers(BitSet32 idBits);
+    virtual void addMovement(nsecs_t eventTime, BitSet32 idBits,
+            const VelocityTracker::Position* positions);
+    virtual bool getEstimator(uint32_t id, VelocityTracker::Estimator* outEstimator) const;
+
+private:
+    // Sample horizon.
+    // We don't use too much history by default since we want to react to quick
+    // changes in direction.
+    static constexpr nsecs_t HORIZON = 100 * 1000000; // 100 ms
+
+    // Number of samples to keep.
+    static constexpr size_t HISTORY_SIZE = 20;
+
+    struct Movement {
+        nsecs_t eventTime;
+        BitSet32 idBits;
+        VelocityTracker::Position positions[MAX_POINTERS];
+
+        inline const VelocityTracker::Position& getPosition(uint32_t id) const {
+            return positions[idBits.getIndexOfBit(id)];
+        }
+    };
+
+    size_t mIndex;
+    Movement mMovements[HISTORY_SIZE];
+};
+
 } // namespace android
 
 #endif // _LIBINPUT_VELOCITY_TRACKER_H
diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index 9b06e63..573f685 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -45,6 +45,8 @@
     output.writeInt32(overrideScalingMode);
     output.writeStrongBinder(IInterface::asBinder(barrierGbp));
     output.writeStrongBinder(relativeLayerHandle);
+    output.writeStrongBinder(parentHandleForChild);
+    output.writeStrongBinder(childHandle);
     output.write(transparentRegion);
     return NO_ERROR;
 }
@@ -77,6 +79,8 @@
     barrierGbp =
         interface_cast<IGraphicBufferProducer>(input.readStrongBinder());
     relativeLayerHandle = input.readStrongBinder();
+    parentHandleForChild = input.readStrongBinder();
+    childHandle = input.readStrongBinder();
     input.read(transparentRegion);
     return NO_ERROR;
 }
diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index 5b1c599..6c9d88b 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -1509,6 +1509,12 @@
     return NO_ERROR;
 }
 
+android_dataspace_t Surface::getBuffersDataSpace() {
+    ALOGV("Surface::getBuffersDataSpace");
+    Mutex::Autolock lock(mMutex);
+    return mDataSpace;
+}
+
 void Surface::freeAllBuffers() {
     for (int i = 0; i < NUM_BUFFER_SLOTS; i++) {
         mSlots[i].buffer = 0;
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index 7ae2672..b0ae7e0 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -176,6 +176,9 @@
     status_t reparentChildren(const sp<SurfaceComposerClient>& client,
             const sp<IBinder>& id,
             const sp<IBinder>& newParentHandle);
+    status_t reparentChild(const sp<SurfaceComposerClient>& client,
+            const sp<IBinder>& id, const sp<IBinder>& newParentHandle,
+            const sp<IBinder>& childHandle);
     status_t detachChildren(const sp<SurfaceComposerClient>& client,
             const sp<IBinder>& id);
     status_t setOverrideScalingMode(const sp<SurfaceComposerClient>& client,
@@ -493,6 +496,21 @@
     return NO_ERROR;
 }
 
+status_t Composer::reparentChild(const sp<SurfaceComposerClient>& client,
+        const sp<IBinder>& id,
+        const sp<IBinder>& newParentHandle,
+        const sp<IBinder>& childHandle) {
+    Mutex::Autolock lock(mLock);
+    layer_state_t* s = getLayerStateLocked(client, id);
+    if (!s) {
+        return BAD_INDEX;
+    }
+    s->what |= layer_state_t::eReparentChild;
+    s->parentHandleForChild = newParentHandle;
+    s->childHandle = childHandle;
+    return NO_ERROR;
+}
+
 status_t Composer::detachChildren(
         const sp<SurfaceComposerClient>& client,
         const sp<IBinder>& id) {
@@ -831,6 +849,11 @@
     return getComposer().reparentChildren(this, id, newParentHandle);
 }
 
+status_t SurfaceComposerClient::reparentChild(const sp<IBinder>& id,
+        const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle) {
+    return getComposer().reparentChild(this, id, newParentHandle, childHandle);
+}
+
 status_t SurfaceComposerClient::detachChildren(const sp<IBinder>& id) {
     return getComposer().detachChildren(this, id);
 }
diff --git a/libs/gui/SurfaceControl.cpp b/libs/gui/SurfaceControl.cpp
index 58bd273..b9c5ef9 100644
--- a/libs/gui/SurfaceControl.cpp
+++ b/libs/gui/SurfaceControl.cpp
@@ -191,6 +191,13 @@
     return mClient->reparentChildren(mHandle, newParentHandle);
 }
 
+status_t SurfaceControl::reparentChild(const sp<IBinder>& newParentHandle,
+        const sp<IBinder>& childHandle) {
+    status_t err = validate();
+    if (err < 0) return err;
+    return mClient->reparentChild(mHandle, newParentHandle, childHandle);
+}
+
 status_t SurfaceControl::detachChildren() {
     status_t err = validate();
     if (err < 0) return err;
diff --git a/libs/gui/include/gui/Surface.h b/libs/gui/include/gui/Surface.h
index 55dd6bf..3fe29d9 100644
--- a/libs/gui/include/gui/Surface.h
+++ b/libs/gui/include/gui/Surface.h
@@ -281,6 +281,8 @@
     // detachNextBuffer, or attachBuffer call.
     status_t getAndFlushRemovedBuffers(std::vector<sp<GraphicBuffer>>* out);
 
+    android_dataspace_t getBuffersDataSpace();
+
 protected:
     enum { NUM_BUFFER_SLOTS = BufferQueueDefs::NUM_BUFFER_SLOTS };
     enum { DEFAULT_FORMAT = PIXEL_FORMAT_RGBA_8888 };
diff --git a/libs/gui/include/gui/SurfaceComposerClient.h b/libs/gui/include/gui/SurfaceComposerClient.h
index 145c059..6e2cb83 100644
--- a/libs/gui/include/gui/SurfaceComposerClient.h
+++ b/libs/gui/include/gui/SurfaceComposerClient.h
@@ -161,6 +161,8 @@
             const sp<Surface>& handle, uint64_t frameNumber);
     status_t    reparentChildren(const sp<IBinder>& id,
             const sp<IBinder>& newParentHandle);
+    status_t    reparentChild(const sp<IBinder>& id, const sp<IBinder>& newParentHandle,
+            const sp<IBinder>& childHandle);
     status_t    detachChildren(const sp<IBinder>& id);
     status_t    setOverrideScalingMode(const sp<IBinder>& id,
             int32_t overrideScalingMode);
diff --git a/libs/gui/include/gui/SurfaceControl.h b/libs/gui/include/gui/SurfaceControl.h
index c15209d..d8b67ef 100644
--- a/libs/gui/include/gui/SurfaceControl.h
+++ b/libs/gui/include/gui/SurfaceControl.h
@@ -124,6 +124,12 @@
     // Reparents all children of this layer to the new parent handle.
     status_t reparentChildren(const sp<IBinder>& newParentHandle);
 
+    // Reparents a specified child from this layer to the new parent handle.
+    // The child, parent, and new parent must all have the same client.
+    // This can be used instead of reparentChildren if the caller wants to
+    // only re-parent specific children.
+    status_t reparentChild(const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle);
+
     // Detaches all child surfaces (and their children recursively)
     // from their SurfaceControl.
     // The child SurfaceControl's will not throw exceptions or return errors,
diff --git a/libs/gui/include/private/gui/LayerState.h b/libs/gui/include/private/gui/LayerState.h
index 307c764..4f73e04 100644
--- a/libs/gui/include/private/gui/LayerState.h
+++ b/libs/gui/include/private/gui/LayerState.h
@@ -59,7 +59,8 @@
         eGeometryAppliesWithResize  = 0x00001000,
         eReparentChildren           = 0x00002000,
         eDetachChildren             = 0x00004000,
-        eRelativeLayerChanged       = 0x00008000
+        eRelativeLayerChanged       = 0x00008000,
+        eReparentChild              = 0x00010000
     };
 
     layer_state_t()
@@ -107,6 +108,9 @@
 
             sp<IBinder>     relativeLayerHandle;
 
+            sp<IBinder>     parentHandleForChild;
+            sp<IBinder>     childHandle;
+
             // non POD must be last. see write/read
             Region          transparentRegion;
 };
diff --git a/libs/input/VelocityTracker.cpp b/libs/input/VelocityTracker.cpp
index 62acea3..f5b896b 100644
--- a/libs/input/VelocityTracker.cpp
+++ b/libs/input/VelocityTracker.cpp
@@ -75,7 +75,9 @@
     str += " ]";
     return str;
 }
+#endif
 
+#if DEBUG_STRATEGY
 static std::string matrixToString(const float* a, uint32_t m, uint32_t n, bool rowMajor) {
     std::string str;
     str = "[";
@@ -141,6 +143,11 @@
 }
 
 VelocityTrackerStrategy* VelocityTracker::createStrategy(const char* strategy) {
+    if (!strcmp("impulse", strategy)) {
+        // Physical model of pushing an object.  Quality: VERY GOOD.
+        // Works with duplicate coordinates, unclean finger liftoff.
+        return new ImpulseVelocityTrackerStrategy();
+    }
     if (!strcmp("lsq1", strategy)) {
         // 1st order least squares.  Quality: POOR.
         // Frequently underfits the touch data especially when the finger accelerates
@@ -352,9 +359,6 @@
 
 // --- LeastSquaresVelocityTrackerStrategy ---
 
-const nsecs_t LeastSquaresVelocityTrackerStrategy::HORIZON;
-const uint32_t LeastSquaresVelocityTrackerStrategy::HISTORY_SIZE;
-
 LeastSquaresVelocityTrackerStrategy::LeastSquaresVelocityTrackerStrategy(
         uint32_t degree, Weighting weighting) :
         mDegree(degree), mWeighting(weighting) {
@@ -863,10 +867,6 @@
 
 // --- LegacyVelocityTrackerStrategy ---
 
-const nsecs_t LegacyVelocityTrackerStrategy::HORIZON;
-const uint32_t LegacyVelocityTrackerStrategy::HISTORY_SIZE;
-const nsecs_t LegacyVelocityTrackerStrategy::MIN_DURATION;
-
 LegacyVelocityTrackerStrategy::LegacyVelocityTrackerStrategy() {
     clear();
 }
@@ -979,4 +979,192 @@
     return true;
 }
 
+// --- ImpulseVelocityTrackerStrategy ---
+
+ImpulseVelocityTrackerStrategy::ImpulseVelocityTrackerStrategy() {
+    clear();
+}
+
+ImpulseVelocityTrackerStrategy::~ImpulseVelocityTrackerStrategy() {
+}
+
+void ImpulseVelocityTrackerStrategy::clear() {
+    mIndex = 0;
+    mMovements[0].idBits.clear();
+}
+
+void ImpulseVelocityTrackerStrategy::clearPointers(BitSet32 idBits) {
+    BitSet32 remainingIdBits(mMovements[mIndex].idBits.value & ~idBits.value);
+    mMovements[mIndex].idBits = remainingIdBits;
+}
+
+void ImpulseVelocityTrackerStrategy::addMovement(nsecs_t eventTime, BitSet32 idBits,
+        const VelocityTracker::Position* positions) {
+    if (++mIndex == HISTORY_SIZE) {
+        mIndex = 0;
+    }
+
+    Movement& movement = mMovements[mIndex];
+    movement.eventTime = eventTime;
+    movement.idBits = idBits;
+    uint32_t count = idBits.count();
+    for (uint32_t i = 0; i < count; i++) {
+        movement.positions[i] = positions[i];
+    }
+}
+
+/**
+ * Calculate the total impulse provided to the screen and the resulting velocity.
+ *
+ * The touchscreen is modeled as a physical object.
+ * Initial condition is discussed below, but for now suppose that v(t=0) = 0
+ *
+ * The kinetic energy of the object at the release is E=0.5*m*v^2
+ * Then vfinal = sqrt(2E/m). The goal is to calculate E.
+ *
+ * The kinetic energy at the release is equal to the total work done on the object by the finger.
+ * The total work W is the sum of all dW along the path.
+ *
+ * dW = F*dx, where dx is the piece of path traveled.
+ * Force is change of momentum over time, F = dp/dt = m dv/dt.
+ * Then substituting:
+ * dW = m (dv/dt) * dx = m * v * dv
+ *
+ * Summing along the path, we get:
+ * W = sum(dW) = sum(m * v * dv) = m * sum(v * dv)
+ * Since the mass stays constant, the equation for final velocity is:
+ * vfinal = sqrt(2*sum(v * dv))
+ *
+ * Here,
+ * dv : change of velocity = (v[i+1]-v[i])
+ * dx : change of distance = (x[i+1]-x[i])
+ * dt : change of time = (t[i+1]-t[i])
+ * v : instantaneous velocity = dx/dt
+ *
+ * The final formula is:
+ * vfinal = sqrt(2) * sqrt(sum((v[i]-v[i-1])*|v[i]|)) for all i
+ * The absolute value is needed to properly account for the sign. If the velocity over a
+ * particular segment descreases, then this indicates braking, which means that negative
+ * work was done. So for two positive, but decreasing, velocities, this contribution would be
+ * negative and will cause a smaller final velocity.
+ *
+ * Initial condition
+ * There are two ways to deal with initial condition:
+ * 1) Assume that v(0) = 0, which would mean that the screen is initially at rest.
+ * This is not entirely accurate. We are only taking the past X ms of touch data, where X is
+ * currently equal to 100. However, a touch event that created a fling probably lasted for longer
+ * than that, which would mean that the user has already been interacting with the touchscreen
+ * and it has probably already been moving.
+ * 2) Assume that the touchscreen has already been moving at a certain velocity, calculate this
+ * initial velocity and the equivalent energy, and start with this initial energy.
+ * Consider an example where we have the following data, consisting of 3 points:
+ *                 time: t0, t1, t2
+ *                 x   : x0, x1, x2
+ *                 v   : 0 , v1, v2
+ * Here is what will happen in each of these scenarios:
+ * 1) By directly applying the formula above with the v(0) = 0 boundary condition, we will get
+ * vfinal = sqrt(2*(|v1|*(v1-v0) + |v2|*(v2-v1))). This can be simplified since v0=0
+ * vfinal = sqrt(2*(|v1|*v1 + |v2|*(v2-v1))) = sqrt(2*(v1^2 + |v2|*(v2 - v1)))
+ * since velocity is a real number
+ * 2) If we treat the screen as already moving, then it must already have an energy (per mass)
+ * equal to 1/2*v1^2. Then the initial energy should be 1/2*v1*2, and only the second segment
+ * will contribute to the total kinetic energy (since we can effectively consider that v0=v1).
+ * This will give the following expression for the final velocity:
+ * vfinal = sqrt(2*(1/2*v1^2 + |v2|*(v2-v1)))
+ * This analysis can be generalized to an arbitrary number of samples.
+ *
+ *
+ * Comparing the two equations above, we see that the only mathematical difference
+ * is the factor of 1/2 in front of the first velocity term.
+ * This boundary condition would allow for the "proper" calculation of the case when all of the
+ * samples are equally spaced in time and distance, which should suggest a constant velocity.
+ *
+ * Note that approach 2) is sensitive to the proper ordering of the data in time, since
+ * the boundary condition must be applied to the oldest sample to be accurate.
+ */
+static float calculateImpulseVelocity(const nsecs_t* t, const float* x, size_t count) {
+    // The input should be in reversed time order (most recent sample at index i=0)
+    // t[i] is in nanoseconds, but due to FP arithmetic, convert to seconds inside this function
+    static constexpr float NANOS_PER_SECOND = 1E-9;
+    static constexpr float sqrt2 = 1.41421356237;
+
+    if (count < 2) {
+        return 0; // if 0 or 1 points, velocity is zero
+    }
+    if (t[1] > t[0]) { // Algorithm will still work, but not perfectly
+        ALOGE("Samples provided to calculateImpulseVelocity in the wrong order");
+    }
+    if (count == 2) { // if 2 points, basic linear calculation
+        if (t[1] == t[0]) {
+            ALOGE("Events have identical time stamps t=%" PRId64 ", setting velocity = 0", t[0]);
+            return 0;
+        }
+        return (x[1] - x[0]) / (NANOS_PER_SECOND * (t[1] - t[0]));
+    }
+    // Guaranteed to have at least 3 points here
+    float work = 0;
+    float vprev, vcurr; // v[i-1] and v[i], respectively
+    vprev = 0;
+    for (size_t i = count - 1; i > 0 ; i--) { // start with the oldest sample and go forward in time
+        if (t[i] == t[i-1]) {
+            ALOGE("Events have identical time stamps t=%" PRId64 ", skipping sample", t[i]);
+            continue;
+        }
+        vcurr = (x[i] - x[i-1]) / (NANOS_PER_SECOND * (t[i] - t[i-1]));
+        work += (vcurr - vprev) * fabsf(vcurr);
+        if (i == count - 1) {
+            work *= 0.5; // initial condition, case 2) above
+        }
+        vprev = vcurr;
+    }
+    return (work < 0 ? -1.0 : 1.0) * sqrtf(fabsf(work)) * sqrt2;
+}
+
+bool ImpulseVelocityTrackerStrategy::getEstimator(uint32_t id,
+        VelocityTracker::Estimator* outEstimator) const {
+    outEstimator->clear();
+
+    // Iterate over movement samples in reverse time order and collect samples.
+    float x[HISTORY_SIZE];
+    float y[HISTORY_SIZE];
+    nsecs_t time[HISTORY_SIZE];
+    size_t m = 0; // number of points that will be used for fitting
+    size_t index = mIndex;
+    const Movement& newestMovement = mMovements[mIndex];
+    do {
+        const Movement& movement = mMovements[index];
+        if (!movement.idBits.hasBit(id)) {
+            break;
+        }
+
+        nsecs_t age = newestMovement.eventTime - movement.eventTime;
+        if (age > HORIZON) {
+            break;
+        }
+
+        const VelocityTracker::Position& position = movement.getPosition(id);
+        x[m] = position.x;
+        y[m] = position.y;
+        time[m] = movement.eventTime;
+        index = (index == 0 ? HISTORY_SIZE : index) - 1;
+    } while (++m < HISTORY_SIZE);
+
+    if (m == 0) {
+        return false; // no data
+    }
+    outEstimator->xCoeff[0] = 0;
+    outEstimator->yCoeff[0] = 0;
+    outEstimator->xCoeff[1] = calculateImpulseVelocity(time, x, m);
+    outEstimator->yCoeff[1] = calculateImpulseVelocity(time, y, m);
+    outEstimator->xCoeff[2] = 0;
+    outEstimator->yCoeff[2] = 0;
+    outEstimator->time = newestMovement.eventTime;
+    outEstimator->degree = 2; // similar results to 2nd degree fit
+    outEstimator->confidence = 1;
+#if DEBUG_STRATEGY
+    ALOGD("velocity: (%f, %f)", outEstimator->xCoeff[1], outEstimator->yCoeff[1]);
+#endif
+    return true;
+}
+
 } // namespace android
diff --git a/libs/input/tests/Android.bp b/libs/input/tests/Android.bp
index 029a420..e3e1dec 100644
--- a/libs/input/tests/Android.bp
+++ b/libs/input/tests/Android.bp
@@ -6,6 +6,7 @@
         "InputChannel_test.cpp",
         "InputEvent_test.cpp",
         "InputPublisherAndConsumer_test.cpp",
+        "VelocityTracker_test.cpp",
     ],
     shared_libs: [
         "libinput",
@@ -13,6 +14,7 @@
         "libutils",
         "libbinder",
         "libui",
+        "libbase",
     ]
 }
 
diff --git a/libs/input/tests/VelocityTracker_test.cpp b/libs/input/tests/VelocityTracker_test.cpp
new file mode 100644
index 0000000..43b6012
--- /dev/null
+++ b/libs/input/tests/VelocityTracker_test.cpp
@@ -0,0 +1,664 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "VelocityTracker_test"
+
+#include <math.h>
+
+#include <android-base/stringprintf.h>
+#include <gtest/gtest.h>
+#include <input/VelocityTracker.h>
+
+using android::base::StringPrintf;
+
+namespace android {
+
+constexpr int32_t DEFAULT_POINTER_ID = 0; // pointer ID used for manually defined tests
+
+// velocity must be in the range (1-tol)*EV <= velocity <= (1+tol)*EV
+// here EV = expected value, tol = VELOCITY_TOLERANCE
+constexpr float VELOCITY_TOLERANCE = 0.2;
+
+// --- VelocityTrackerTest ---
+class VelocityTrackerTest : public testing::Test { };
+
+static void checkVelocity(float Vactual, float Vtarget) {
+    // Compare directions
+    if ((Vactual > 0 && Vtarget <= 0) || (Vactual < 0 && Vtarget >= 0)) {
+        FAIL() << StringPrintf("Velocity %f does not have the same direction"
+                " as the target velocity %f", Vactual, Vtarget);
+    }
+
+    // Compare magnitudes
+    const float Vlower = fabsf(Vtarget * (1 - VELOCITY_TOLERANCE));
+    const float Vupper = fabsf(Vtarget * (1 + VELOCITY_TOLERANCE));
+    if (fabsf(Vactual) < Vlower) {
+        FAIL() << StringPrintf("Velocity %f is more than %.0f%% below target velocity %f",
+                Vactual, VELOCITY_TOLERANCE * 100, Vtarget);
+    }
+    if (fabsf(Vactual) > Vupper) {
+        FAIL() << StringPrintf("Velocity %f is more than %.0f%% above target velocity %f",
+                Vactual, VELOCITY_TOLERANCE * 100, Vtarget);
+    }
+    SUCCEED() << StringPrintf("Velocity %f within %.0f%% of target %f)",
+            Vactual, VELOCITY_TOLERANCE * 100, Vtarget);
+}
+
+void failWithMessage(std::string message) {
+    FAIL() << message; // cannot do this directly from a non-void function
+}
+
+struct Position {
+      nsecs_t time;
+      float x;
+      float y;
+};
+
+
+MotionEvent* createSimpleMotionEvent(const Position* positions, size_t numSamples) {
+    /**
+     * Only populate the basic fields of a MotionEvent, such as time and a single axis
+     * Designed for use with manually-defined tests.
+     * Create a new MotionEvent on the heap, caller responsible for destroying the object.
+     */
+    if (numSamples < 1) {
+        failWithMessage(StringPrintf("Need at least 1 sample to create a MotionEvent."
+                " Received numSamples=%zu", numSamples));
+    }
+
+    MotionEvent* event = new MotionEvent();
+    PointerCoords coords;
+    PointerProperties properties[1];
+
+    properties[0].id = DEFAULT_POINTER_ID;
+    properties[0].toolType = AMOTION_EVENT_TOOL_TYPE_FINGER;
+
+    // First sample added separately with initialize
+    coords.setAxisValue(AMOTION_EVENT_AXIS_X, positions[0].x);
+    coords.setAxisValue(AMOTION_EVENT_AXIS_Y, positions[0].y);
+    event->initialize(0, AINPUT_SOURCE_TOUCHSCREEN, AMOTION_EVENT_ACTION_MOVE,
+            0, 0, 0, 0, 0, 0, 0, 0, 0, 0, positions[0].time, 1, properties, &coords);
+
+    for (size_t i = 1; i < numSamples; i++) {
+        coords.setAxisValue(AMOTION_EVENT_AXIS_X, positions[i].x);
+        coords.setAxisValue(AMOTION_EVENT_AXIS_Y, positions[i].y);
+        event->addSample(positions[i].time, &coords);
+    }
+    return event;
+}
+
+static void computeAndCheckVelocity(const Position* positions, size_t numSamples,
+            int32_t axis, float targetVelocity) {
+    VelocityTracker vt(nullptr);
+    float Vx, Vy;
+
+    MotionEvent* event = createSimpleMotionEvent(positions, numSamples);
+    vt.addMovement(event);
+
+    vt.getVelocity(DEFAULT_POINTER_ID, &Vx, &Vy);
+
+    switch (axis) {
+    case AMOTION_EVENT_AXIS_X:
+        checkVelocity(Vx, targetVelocity);
+        break;
+    case AMOTION_EVENT_AXIS_Y:
+        checkVelocity(Vy, targetVelocity);
+        break;
+    default:
+        FAIL() << "Axis must be either AMOTION_EVENT_AXIS_X or AMOTION_EVENT_AXIS_Y";
+    }
+    delete event;
+}
+
+/*
+ * ================== VelocityTracker tests generated manually =====================================
+ */
+ // @todo Currently disabled, enable when switching away from lsq2 VelocityTrackerStrategy
+TEST_F(VelocityTrackerTest, DISABLED_ThreePointsPositiveVelocityTest) {
+    // Same coordinate is reported 2 times in a row
+    // It is difficult to determine the correct answer here, but at least the direction
+    // of the reported velocity should be positive.
+    Position values[] = {
+        { 0, 273, NAN },
+        { 12585000, 293, NAN },
+        { 14730000, 293, NAN },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 1600);
+}
+
+TEST_F(VelocityTrackerTest, ThreePointsZeroVelocityTest) {
+    // Same coordinate is reported 3 times in a row
+    Position values[] = {
+        { 0, 293, NAN },
+        { 6132000, 293, NAN },
+        { 11283000, 293, NAN },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 0);
+}
+
+TEST_F(VelocityTrackerTest, ThreePointsLinearVelocityTest) {
+    // Fixed velocity at 5 points per 10 milliseconds
+    Position values[] = {
+        { 0, 0, NAN },
+        { 10000000, 5, NAN },
+        { 20000000, 10, NAN },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 500);
+}
+
+
+/**
+ * ================== VelocityTracker tests generated by recording real events =====================
+ *
+ * To add a test, record the input coordinates and event times to all calls
+ * to void VelocityTracker::addMovement(const MotionEvent* event).
+ * Also record all calls to VelocityTracker::clear().
+ * Finally, record the output of VelocityTracker::getVelocity(...)
+ * This will give you the necessary data to create a new test.
+ */
+
+// --------------- Recorded by hand on swordfish ---------------------------------------------------
+// @todo Currently disabled, enable when switching away from lsq2 VelocityTrackerStrategy
+TEST_F(VelocityTrackerTest, DISABLED_SwordfishFlingDown) {
+    // Recording of a fling on Swordfish that could cause a fling in the wrong direction
+    Position values[] = {
+        { 0, 271, 96 },
+        { 16071042, 269.786346, 106.922775 },
+        { 35648403, 267.983063, 156.660034 },
+        { 52313925, 262.638397, 220.339081 },
+        { 68976522, 266.138824, 331.581116 },
+        { 85639375, 274.79245, 428.113159 },
+        { 96948871, 274.79245, 428.113159 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 623.577637);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 8523.348633);
+}
+
+// --------------- Recorded by hand on sailfish, generated by a script -----------------------------
+// For some of these tests, the X-direction velocity checking has been removed, because the lsq2
+// and the impulse VelocityTrackerStrategies did not agree within 20%.
+// Since the flings were recorded in the Y-direction, the intentional user action should only
+// be relevant for the Y axis.
+// There have been also cases where lsq2 and impulse disagreed more than 20% in the Y-direction.
+// Those recordings have been discarded because we didn't feel one strategy's interpretation was
+// more correct than another's but didn't want to increase the tolerance for the entire test suite.
+//
+// There are 18 tests total below: 9 in the positive Y direction and 9 in the opposite.
+// The recordings were loosely binned into 3 categories - slow, faster, and fast, which roughly
+// characterizes the velocity of the finger motion.
+// These can be treated approximately as:
+// slow - less than 1 page gets scrolled
+// faster - more than 1 page gets scrolled, but less than 3
+// fast - entire list is scrolled (fling is done as hard as possible)
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpSlow1) {
+    // Sailfish - fling up - slow - 1
+    Position values[] = {
+        { 235089067457000, 528.00, 983.00 },
+        { 235089084684000, 527.00, 981.00 },
+        { 235089093349000, 527.00, 977.00 },
+        { 235089095677625, 527.00, 975.93 },
+        { 235089101859000, 527.00, 970.00 },
+        { 235089110378000, 528.00, 960.00 },
+        { 235089112497111, 528.25, 957.51 },
+        { 235089118760000, 531.00, 946.00 },
+        { 235089126686000, 535.00, 931.00 },
+        { 235089129316820, 536.33, 926.02 },
+        { 235089135199000, 540.00, 914.00 },
+        { 235089144297000, 546.00, 896.00 },
+        { 235089146136443, 547.21, 892.36 },
+        { 235089152923000, 553.00, 877.00 },
+        { 235089160784000, 559.00, 851.00 },
+        { 235089162955851, 560.66, 843.82 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 872.794617); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 951.698181); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -3604.819336); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -3044.966064); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpSlow2) {
+    // Sailfish - fling up - slow - 2
+    Position values[] = {
+        { 235110560704000, 522.00, 1107.00 },
+        { 235110575764000, 522.00, 1107.00 },
+        { 235110584385000, 522.00, 1107.00 },
+        { 235110588421179, 521.52, 1106.52 },
+        { 235110592830000, 521.00, 1106.00 },
+        { 235110601385000, 520.00, 1104.00 },
+        { 235110605088160, 519.14, 1102.27 },
+        { 235110609952000, 518.00, 1100.00 },
+        { 235110618353000, 517.00, 1093.00 },
+        { 235110621755146, 516.60, 1090.17 },
+        { 235110627010000, 517.00, 1081.00 },
+        { 235110634785000, 518.00, 1063.00 },
+        { 235110638422450, 518.87, 1052.58 },
+        { 235110643161000, 520.00, 1039.00 },
+        { 235110651767000, 524.00, 1011.00 },
+        { 235110655089581, 525.54, 1000.19 },
+        { 235110660368000, 530.00, 980.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -4096.583008); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -3455.094238); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpSlow3) {
+    // Sailfish - fling up - slow - 3
+    Position values[] = {
+        { 792536237000, 580.00, 1317.00 },
+        { 792541538987, 580.63, 1311.94 },
+        { 792544613000, 581.00, 1309.00 },
+        { 792552301000, 583.00, 1295.00 },
+        { 792558362309, 585.13, 1282.92 },
+        { 792560828000, 586.00, 1278.00 },
+        { 792569446000, 589.00, 1256.00 },
+        { 792575185095, 591.54, 1241.41 },
+        { 792578491000, 593.00, 1233.00 },
+        { 792587044000, 597.00, 1211.00 },
+        { 792592008172, 600.28, 1195.92 },
+        { 792594616000, 602.00, 1188.00 },
+        { 792603129000, 607.00, 1167.00 },
+        { 792608831290, 609.48, 1155.83 },
+        { 792612321000, 611.00, 1149.00 },
+        { 792620768000, 615.00, 1131.00 },
+        { 792625653873, 617.32, 1121.73 },
+        { 792629200000, 619.00, 1115.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 574.33429); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 617.40564); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -2361.982666); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -2500.055664); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpFaster1) {
+    // Sailfish - fling up - faster - 1
+    Position values[] = {
+        { 235160420675000, 610.00, 1042.00 },
+        { 235160428220000, 609.00, 1026.00 },
+        { 235160436544000, 609.00, 1024.00 },
+        { 235160441852394, 609.64, 1020.82 },
+        { 235160444878000, 610.00, 1019.00 },
+        { 235160452673000, 613.00, 1006.00 },
+        { 235160458519743, 617.18, 992.06 },
+        { 235160461061000, 619.00, 986.00 },
+        { 235160469798000, 627.00, 960.00 },
+        { 235160475186713, 632.22, 943.02 },
+        { 235160478051000, 635.00, 934.00 },
+        { 235160486489000, 644.00, 906.00 },
+        { 235160491853697, 649.56, 890.56 },
+        { 235160495177000, 653.00, 881.00 },
+        { 235160504148000, 662.00, 858.00 },
+        { 235160509231495, 666.81, 845.37 },
+        { 235160512603000, 670.00, 837.00 },
+        { 235160520366000, 679.00, 814.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 1274.141724); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 1438.53186); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -3877.35498); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -3695.859619); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpFaster2) {
+    // Sailfish - fling up - faster - 2
+    Position values[] = {
+        { 847153808000, 576.00, 1264.00 },
+        { 847171174000, 576.00, 1262.00 },
+        { 847179640000, 576.00, 1257.00 },
+        { 847185187540, 577.41, 1249.22 },
+        { 847187487000, 578.00, 1246.00 },
+        { 847195710000, 581.00, 1227.00 },
+        { 847202027059, 583.93, 1209.40 },
+        { 847204324000, 585.00, 1203.00 },
+        { 847212672000, 590.00, 1176.00 },
+        { 847218861395, 594.36, 1157.11 },
+        { 847221190000, 596.00, 1150.00 },
+        { 847230484000, 602.00, 1124.00 },
+        { 847235701400, 607.56, 1103.83 },
+        { 847237986000, 610.00, 1095.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -4280.07959); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -4241.004395); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpFaster3) {
+    // Sailfish - fling up - faster - 3
+    Position values[] = {
+        { 235200532789000, 507.00, 1084.00 },
+        { 235200549221000, 507.00, 1083.00 },
+        { 235200557841000, 507.00, 1081.00 },
+        { 235200558051189, 507.00, 1080.95 },
+        { 235200566314000, 507.00, 1078.00 },
+        { 235200574876586, 508.97, 1070.12 },
+        { 235200575006000, 509.00, 1070.00 },
+        { 235200582900000, 514.00, 1054.00 },
+        { 235200591276000, 525.00, 1023.00 },
+        { 235200591701829, 525.56, 1021.42 },
+        { 235200600064000, 542.00, 976.00 },
+        { 235200608519000, 563.00, 911.00 },
+        { 235200608527086, 563.02, 910.94 },
+        { 235200616933000, 590.00, 844.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -8715.686523); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -7639.026367); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpFast1) {
+    // Sailfish - fling up - fast - 1
+    Position values[] = {
+        { 920922149000, 561.00, 1412.00 },
+        { 920930185000, 559.00, 1377.00 },
+        { 920930262463, 558.98, 1376.66 },
+        { 920938547000, 559.00, 1371.00 },
+        { 920947096857, 562.91, 1342.68 },
+        { 920947302000, 563.00, 1342.00 },
+        { 920955502000, 577.00, 1272.00 },
+        { 920963931021, 596.87, 1190.54 },
+        { 920963987000, 597.00, 1190.00 },
+        { 920972530000, 631.00, 1093.00 },
+        { 920980765511, 671.31, 994.68 },
+        { 920980906000, 672.00, 993.00 },
+        { 920989261000, 715.00, 903.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 5670.329102); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, 5991.866699); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -13021.101562); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -15093.995117); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpFast2) {
+    // Sailfish - fling up - fast - 2
+    Position values[] = {
+        { 235247153233000, 518.00, 1168.00 },
+        { 235247170452000, 517.00, 1167.00 },
+        { 235247178908000, 515.00, 1159.00 },
+        { 235247179556213, 514.85, 1158.39 },
+        { 235247186821000, 515.00, 1125.00 },
+        { 235247195265000, 521.00, 1051.00 },
+        { 235247196389476, 521.80, 1041.15 },
+        { 235247203649000, 538.00, 932.00 },
+        { 235247212253000, 571.00, 794.00 },
+        { 235247213222491, 574.72, 778.45 },
+        { 235247220736000, 620.00, 641.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -20286.958984); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -20494.587891); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingUpFast3) {
+    // Sailfish - fling up - fast - 3
+    Position values[] = {
+        { 235302568736000, 529.00, 1167.00 },
+        { 235302576644000, 523.00, 1140.00 },
+        { 235302579395063, 520.91, 1130.61 },
+        { 235302585140000, 522.00, 1130.00 },
+        { 235302593615000, 527.00, 1065.00 },
+        { 235302596207444, 528.53, 1045.12 },
+        { 235302602102000, 559.00, 872.00 },
+        { 235302610545000, 652.00, 605.00 },
+        { 235302613019881, 679.26, 526.73 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -39295.941406); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, -36461.421875); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownSlow1) {
+    // Sailfish - fling down - slow - 1
+    Position values[] = {
+        { 235655749552755, 582.00, 432.49 },
+        { 235655750638000, 582.00, 433.00 },
+        { 235655758865000, 582.00, 440.00 },
+        { 235655766221523, 581.16, 448.43 },
+        { 235655767594000, 581.00, 450.00 },
+        { 235655776044000, 580.00, 462.00 },
+        { 235655782890696, 579.18, 474.35 },
+        { 235655784360000, 579.00, 477.00 },
+        { 235655792795000, 578.00, 496.00 },
+        { 235655799559531, 576.27, 515.04 },
+        { 235655800612000, 576.00, 518.00 },
+        { 235655809535000, 574.00, 542.00 },
+        { 235655816988015, 572.17, 564.86 },
+        { 235655817685000, 572.00, 567.00 },
+        { 235655825981000, 569.00, 595.00 },
+        { 235655833808653, 566.26, 620.60 },
+        { 235655834541000, 566.00, 623.00 },
+        { 235655842893000, 563.00, 649.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -419.749695); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -398.303894); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 3309.016357); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 3969.099854); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownSlow2) {
+    // Sailfish - fling down - slow - 2
+    Position values[] = {
+        { 235671152083370, 485.24, 558.28 },
+        { 235671154126000, 485.00, 559.00 },
+        { 235671162497000, 484.00, 566.00 },
+        { 235671168750511, 483.27, 573.29 },
+        { 235671171071000, 483.00, 576.00 },
+        { 235671179390000, 482.00, 588.00 },
+        { 235671185417210, 481.31, 598.98 },
+        { 235671188173000, 481.00, 604.00 },
+        { 235671196371000, 480.00, 624.00 },
+        { 235671202084196, 479.27, 639.98 },
+        { 235671204235000, 479.00, 646.00 },
+        { 235671212554000, 478.00, 673.00 },
+        { 235671219471011, 476.39, 697.12 },
+        { 235671221159000, 476.00, 703.00 },
+        { 235671229592000, 474.00, 734.00 },
+        { 235671236281462, 472.43, 758.38 },
+        { 235671238098000, 472.00, 765.00 },
+        { 235671246532000, 470.00, 799.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -262.80426); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -243.665344); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 4215.682129); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 4587.986816); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownSlow3) {
+    // Sailfish - fling down - slow - 3
+    Position values[] = {
+        { 170983201000, 557.00, 533.00 },
+        { 171000668000, 556.00, 534.00 },
+        { 171007359750, 554.73, 535.27 },
+        { 171011197000, 554.00, 536.00 },
+        { 171017660000, 552.00, 540.00 },
+        { 171024201831, 549.97, 544.73 },
+        { 171027333000, 549.00, 547.00 },
+        { 171034603000, 545.00, 557.00 },
+        { 171041043371, 541.98, 567.55 },
+        { 171043147000, 541.00, 571.00 },
+        { 171051052000, 536.00, 586.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -723.413513); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -651.038452); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 2091.502441); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 1934.517456); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownFaster1) {
+    // Sailfish - fling down - faster - 1
+    Position values[] = {
+        { 235695280333000, 558.00, 451.00 },
+        { 235695283971237, 558.43, 454.45 },
+        { 235695289038000, 559.00, 462.00 },
+        { 235695297388000, 561.00, 478.00 },
+        { 235695300638465, 561.83, 486.25 },
+        { 235695305265000, 563.00, 498.00 },
+        { 235695313591000, 564.00, 521.00 },
+        { 235695317305492, 564.43, 532.68 },
+        { 235695322181000, 565.00, 548.00 },
+        { 235695330709000, 565.00, 577.00 },
+        { 235695333972227, 565.00, 588.10 },
+        { 235695339250000, 565.00, 609.00 },
+        { 235695347839000, 565.00, 642.00 },
+        { 235695351313257, 565.00, 656.18 },
+        { 235695356412000, 565.00, 677.00 },
+        { 235695364899000, 563.00, 710.00 },
+        { 235695368118682, 562.24, 722.52 },
+        { 235695373403000, 564.00, 744.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 4254.639648); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 4698.415039); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownFaster2) {
+    // Sailfish - fling down - faster - 2
+    Position values[] = {
+        { 235709624766000, 535.00, 579.00 },
+        { 235709642256000, 534.00, 580.00 },
+        { 235709643350278, 533.94, 580.06 },
+        { 235709650760000, 532.00, 584.00 },
+        { 235709658615000, 530.00, 593.00 },
+        { 235709660170495, 529.60, 594.78 },
+        { 235709667095000, 527.00, 606.00 },
+        { 235709675616000, 524.00, 628.00 },
+        { 235709676983261, 523.52, 631.53 },
+        { 235709684289000, 521.00, 652.00 },
+        { 235709692763000, 518.00, 682.00 },
+        { 235709693804993, 517.63, 685.69 },
+        { 235709701438000, 515.00, 709.00 },
+        { 235709709830000, 512.00, 739.00 },
+        { 235709710626776, 511.72, 741.85 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -430.440247); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -447.600311); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 3953.859375); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 4316.155273); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownFaster3) {
+    // Sailfish - fling down - faster - 3
+    Position values[] = {
+        { 235727628927000, 540.00, 440.00 },
+        { 235727636810000, 537.00, 454.00 },
+        { 235727646176000, 536.00, 454.00 },
+        { 235727653586628, 535.12, 456.65 },
+        { 235727654557000, 535.00, 457.00 },
+        { 235727663024000, 534.00, 465.00 },
+        { 235727670410103, 533.04, 479.45 },
+        { 235727670691000, 533.00, 480.00 },
+        { 235727679255000, 531.00, 501.00 },
+        { 235727687233704, 529.09, 526.73 },
+        { 235727687628000, 529.00, 528.00 },
+        { 235727696113000, 526.00, 558.00 },
+        { 235727704057546, 523.18, 588.98 },
+        { 235727704576000, 523.00, 591.00 },
+        { 235727713099000, 520.00, 626.00 },
+        { 235727720880776, 516.33, 655.36 },
+        { 235727721580000, 516.00, 658.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 4484.617676); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 4927.92627); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownFast1) {
+    // Sailfish - fling down - fast - 1
+    Position values[] = {
+        { 235762352849000, 467.00, 286.00 },
+        { 235762360250000, 443.00, 344.00 },
+        { 235762362787412, 434.77, 363.89 },
+        { 235762368807000, 438.00, 359.00 },
+        { 235762377220000, 425.00, 423.00 },
+        { 235762379608561, 421.31, 441.17 },
+        { 235762385698000, 412.00, 528.00 },
+        { 235762394133000, 406.00, 648.00 },
+        { 235762396429369, 404.37, 680.67 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 19084.931641); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 16064.685547); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownFast2) {
+    // Sailfish - fling down - fast - 2
+    Position values[] = {
+        { 235772487188000, 576.00, 204.00 },
+        { 235772495159000, 553.00, 236.00 },
+        { 235772503568000, 551.00, 240.00 },
+        { 235772508192247, 545.55, 254.17 },
+        { 235772512051000, 541.00, 266.00 },
+        { 235772520794000, 520.00, 337.00 },
+        { 235772525015263, 508.92, 394.43 },
+        { 235772529174000, 498.00, 451.00 },
+        { 235772537635000, 484.00, 589.00 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 18660.048828); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 16918.439453); // lsq2
+}
+
+
+TEST_F(VelocityTrackerTest, SailfishFlingDownFast3) {
+    // Sailfish - fling down - fast - 3
+    Position values[] = {
+        { 507650295000, 628.00, 233.00 },
+        { 507658234000, 605.00, 269.00 },
+        { 507666784000, 601.00, 274.00 },
+        { 507669660483, 599.65, 275.68 },
+        { 507675427000, 582.00, 308.00 },
+        { 507683740000, 541.00, 404.00 },
+        { 507686506238, 527.36, 435.95 },
+        { 507692220000, 487.00, 581.00 },
+        { 507700707000, 454.00, 792.00 },
+        { 507703352649, 443.71, 857.77 },
+    };
+    size_t count = sizeof(values) / sizeof(Position);
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -6772.508301); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_X, -6388.48877); // lsq2
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 29765.908203); // impulse
+    computeAndCheckVelocity(values, count, AMOTION_EVENT_AXIS_Y, 28354.796875); // lsq2
+}
+
+
+} // namespace android
diff --git a/libs/sensor/OWNERS b/libs/sensor/OWNERS
new file mode 100644
index 0000000..6a38a1f
--- /dev/null
+++ b/libs/sensor/OWNERS
@@ -0,0 +1,2 @@
+ashutoshj@google.com
+pengxu@google.com
diff --git a/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp b/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
index f9f87ff..6b86433 100644
--- a/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
+++ b/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
@@ -429,7 +429,7 @@
       if (!status) {
         ALOGE(
             "ProducerQueue::FreeAllBuffers: Failed to remove buffer at "
-            "slot=%d.",
+            "slot=%zu.",
             slot);
         last_error = status.error_status();
       }
diff --git a/services/audiomanager/Android.bp b/services/audiomanager/Android.bp
index 22b084a..12ad47e 100644
--- a/services/audiomanager/Android.bp
+++ b/services/audiomanager/Android.bp
@@ -3,7 +3,6 @@
 
     srcs: [
         "IAudioManager.cpp",
-        "IPlayer.cpp",
     ],
 
     shared_libs: [
diff --git a/services/audiomanager/IPlayer.cpp b/services/audiomanager/IPlayer.cpp
deleted file mode 100644
index e8a9c34..0000000
--- a/services/audiomanager/IPlayer.cpp
+++ /dev/null
@@ -1,189 +0,0 @@
-/*
-**
-** Copyright 2017, The Android Open Source Project
-**
-** Licensed under the Apache License, Version 2.0 (the "License");
-** you may not use this file except in compliance with the License.
-** You may obtain a copy of the License at
-**
-**     http://www.apache.org/licenses/LICENSE-2.0
-**
-** Unless required by applicable law or agreed to in writing, software
-** distributed under the License is distributed on an "AS IS" BASIS,
-** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-** See the License for the specific language governing permissions and
-** limitations under the License.
-*/
-
-#define LOG_TAG "IPlayer"
-//#define LOG_NDEBUG 0
-#include <utils/Log.h>
-
-#include <stdint.h>
-#include <sys/types.h>
-
-#include <binder/Parcel.h>
-
-#include <audiomanager/IPlayer.h>
-
-namespace android {
-
-enum {
-    START      = IBinder::FIRST_CALL_TRANSACTION,
-    PAUSE      = IBinder::FIRST_CALL_TRANSACTION + 1,
-    STOP       = IBinder::FIRST_CALL_TRANSACTION + 2,
-    SET_VOLUME = IBinder::FIRST_CALL_TRANSACTION + 3,
-    SET_PAN    = IBinder::FIRST_CALL_TRANSACTION + 4,
-    SET_START_DELAY_MS = IBinder::FIRST_CALL_TRANSACTION + 5,
-    APPLY_VOLUME_SHAPER = IBinder::FIRST_CALL_TRANSACTION + 6,
-};
-
-class BpPlayer : public BpInterface<IPlayer>
-{
-public:
-    explicit BpPlayer(const sp<IBinder>& impl)
-        : BpInterface<IPlayer>(impl)
-    {
-    }
-
-    virtual void start()
-    {
-        Parcel data, reply;
-        data.writeInterfaceToken(IPlayer::getInterfaceDescriptor());
-        remote()->transact(START, data, &reply);
-    }
-
-    virtual void pause()
-    {
-        Parcel data, reply;
-        data.writeInterfaceToken(IPlayer::getInterfaceDescriptor());
-        remote()->transact(PAUSE, data, &reply);
-    }
-
-    virtual void stop()
-    {
-        Parcel data, reply;
-        data.writeInterfaceToken(IPlayer::getInterfaceDescriptor());
-        remote()->transact(STOP, data, &reply);
-    }
-
-    virtual void setVolume(float vol)
-    {
-        Parcel data, reply;
-        data.writeInterfaceToken(IPlayer::getInterfaceDescriptor());
-        data.writeFloat(vol);
-        remote()->transact(SET_VOLUME, data, &reply);
-    }
-
-    virtual void setPan(float pan)
-    {
-        Parcel data, reply;
-        data.writeInterfaceToken(IPlayer::getInterfaceDescriptor());
-        data.writeFloat(pan);
-        remote()->transact(SET_PAN, data, &reply);
-    }
-
-    virtual void setStartDelayMs(int32_t delayMs) {
-        Parcel data, reply;
-        data.writeInterfaceToken(IPlayer::getInterfaceDescriptor());
-        data.writeInt32(delayMs);
-        remote()->transact(SET_START_DELAY_MS, data, &reply);
-    }
-
-    virtual void applyVolumeShaper(
-            const sp<VolumeShaper::Configuration>& configuration,
-            const sp<VolumeShaper::Operation>& operation) {
-        Parcel data, reply;
-        data.writeInterfaceToken(IPlayer::getInterfaceDescriptor());
-
-        status_t status = configuration.get() == nullptr
-                ? data.writeInt32(0)
-                :  data.writeInt32(1)
-                    ?: configuration->writeToParcel(&data);
-        if (status != NO_ERROR) {
-            ALOGW("applyVolumeShaper failed configuration parceling: %d", status);
-            return; // ignore error
-        }
-
-        status = operation.get() == nullptr
-                ? status = data.writeInt32(0)
-                : data.writeInt32(1)
-                    ?: operation->writeToParcel(&data);
-        if (status != NO_ERROR) {
-            ALOGW("applyVolumeShaper failed operation parceling: %d", status);
-            return; // ignore error
-        }
-
-        status = remote()->transact(APPLY_VOLUME_SHAPER, data, &reply);
-
-        ALOGW_IF(status != NO_ERROR, "applyVolumeShaper failed transact: %d", status);
-        return; // one way transaction, ignore error
-    }
-};
-
-IMPLEMENT_META_INTERFACE(Player, "android.media.IPlayer");
-
-// ----------------------------------------------------------------------
-
-status_t BnPlayer::onTransact(
-    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
-{
-    switch (code) {
-        case START: {
-            CHECK_INTERFACE(IPlayer, data, reply);
-            start();
-            return NO_ERROR;
-        } break;
-        case PAUSE: {
-            CHECK_INTERFACE(IPlayer, data, reply);
-            pause();
-            return NO_ERROR;
-        }
-        case STOP: {
-            CHECK_INTERFACE(IPlayer, data, reply);
-            stop();
-            return NO_ERROR;
-        } break;
-        case SET_VOLUME: {
-            CHECK_INTERFACE(IPlayer, data, reply);
-            setVolume(data.readFloat());
-            return NO_ERROR;
-        } break;
-        case SET_PAN: {
-            CHECK_INTERFACE(IPlayer, data, reply);
-            setPan(data.readFloat());
-            return NO_ERROR;
-        } break;
-        case SET_START_DELAY_MS: {
-            CHECK_INTERFACE(IPlayer, data, reply);
-            setStartDelayMs(data.readInt32());
-            return NO_ERROR;
-        } break;
-        case APPLY_VOLUME_SHAPER: {
-            CHECK_INTERFACE(IPlayer, data, reply);
-            sp<VolumeShaper::Configuration> configuration;
-            sp<VolumeShaper::Operation> operation;
-
-            int32_t present;
-            status_t status = data.readInt32(&present);
-            if (status == NO_ERROR && present != 0) {
-                configuration = new VolumeShaper::Configuration();
-                status = configuration->readFromParcel(data);
-            }
-            status = status ?: data.readInt32(&present);
-            if (status == NO_ERROR && present != 0) {
-                operation = new VolumeShaper::Operation();
-                status = operation->readFromParcel(data);
-            }
-            if (status == NO_ERROR) {
-                // one way transaction, no error returned
-                applyVolumeShaper(configuration, operation);
-            }
-            return NO_ERROR;
-        } break;
-        default:
-            return BBinder::onTransact(code, data, reply, flags);
-    }
-}
-
-} // namespace android
diff --git a/services/inputflinger/InputReader.cpp b/services/inputflinger/InputReader.cpp
index 935d0f6..d4266f6 100644
--- a/services/inputflinger/InputReader.cpp
+++ b/services/inputflinger/InputReader.cpp
@@ -257,7 +257,7 @@
         const String8* uniqueDisplayId, DisplayViewport* outViewport) const {
     const DisplayViewport* viewport = NULL;
     if (viewportType == ViewportType::VIEWPORT_VIRTUAL && uniqueDisplayId != NULL) {
-        for (DisplayViewport currentViewport : mVirtualDisplays) {
+        for (const DisplayViewport& currentViewport : mVirtualDisplays) {
             if (currentViewport.uniqueId == *uniqueDisplayId) {
                 viewport = &currentViewport;
                 break;
diff --git a/services/sensorservice/OWNERS b/services/sensorservice/OWNERS
new file mode 100644
index 0000000..6a38a1f
--- /dev/null
+++ b/services/sensorservice/OWNERS
@@ -0,0 +1,2 @@
+ashutoshj@google.com
+pengxu@google.com
diff --git a/services/sensorservice/SensorDevice.cpp b/services/sensorservice/SensorDevice.cpp
index 7d9b0b7..da3b275 100644
--- a/services/sensorservice/SensorDevice.cpp
+++ b/services/sensorservice/SensorDevice.cpp
@@ -223,8 +223,13 @@
 }
 
 void SensorDevice::autoDisable(void *ident, int handle) {
-    Info& info( mActivationCount.editValueFor(handle) );
     Mutex::Autolock _l(mLock);
+    ssize_t activationIndex = mActivationCount.indexOfKey(handle);
+    if (activationIndex < 0) {
+        ALOGW("Handle %d cannot be found in activation record", handle);
+        return;
+    }
+    Info& info(mActivationCount.editValueAt(activationIndex));
     info.removeBatchParamsForIdent(ident);
 }
 
@@ -235,7 +240,12 @@
     bool actuateHardware = false;
 
     Mutex::Autolock _l(mLock);
-    Info& info( mActivationCount.editValueFor(handle) );
+    ssize_t activationIndex = mActivationCount.indexOfKey(handle);
+    if (activationIndex < 0) {
+        ALOGW("Handle %d cannot be found in activation record", handle);
+        return BAD_VALUE;
+    }
+    Info& info(mActivationCount.editValueAt(activationIndex));
 
     ALOGD_IF(DEBUG_CONNECTIONS,
              "SensorDevice::activate: ident=%p, handle=0x%08x, enabled=%d, count=%zu",
@@ -329,7 +339,12 @@
              ident, handle, flags, samplingPeriodNs, maxBatchReportLatencyNs);
 
     Mutex::Autolock _l(mLock);
-    Info& info(mActivationCount.editValueFor(handle));
+    ssize_t activationIndex = mActivationCount.indexOfKey(handle);
+    if (activationIndex < 0) {
+        ALOGW("Handle %d cannot be found in activation record", handle);
+        return BAD_VALUE;
+    }
+    Info& info(mActivationCount.editValueAt(activationIndex));
 
     if (info.batchParams.indexOfKey(ident) < 0) {
         BatchParams params(samplingPeriodNs, maxBatchReportLatencyNs);
diff --git a/services/surfaceflinger/Client.cpp b/services/surfaceflinger/Client.cpp
index 8ba6cb9..ea6541a 100644
--- a/services/surfaceflinger/Client.cpp
+++ b/services/surfaceflinger/Client.cpp
@@ -140,7 +140,8 @@
 {
     sp<Layer> parent = nullptr;
     if (parentHandle != nullptr) {
-        parent = getLayerUser(parentHandle);
+        auto layerHandle = reinterpret_cast<Layer::Handle*>(parentHandle.get());
+        parent = layerHandle->owner.promote();
         if (parent == nullptr) {
             return NAME_NOT_FOUND;
         }
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 248ef53..0244c1b 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -28,6 +28,7 @@
 #include <utils/RefBase.h>
 #include <utils/Log.h>
 
+#include <ui/DebugUtils.h>
 #include <ui/DisplayInfo.h>
 #include <ui/PixelFormat.h>
 
@@ -617,6 +618,7 @@
 
 void DisplayDevice::dump(String8& result) const {
     const Transform& tr(mGlobalTransform);
+    ANativeWindow* const window = mNativeWindow.get();
     EGLint redSize, greenSize, blueSize, alphaSize;
     eglGetConfigAttrib(mDisplay, mConfig, EGL_RED_SIZE, &redSize);
     eglGetConfigAttrib(mDisplay, mConfig, EGL_GREEN_SIZE, &greenSize);
@@ -626,9 +628,9 @@
     result.appendFormat("   type=%x, hwcId=%d, layerStack=%u, (%4dx%4d), ANativeWindow=%p "
                         "(%d:%d:%d:%d), orient=%2d (type=%08x), "
                         "flips=%u, isSecure=%d, powerMode=%d, activeConfig=%d, numLayers=%zu\n",
-                        mType, mHwcDisplayId, mLayerStack, mDisplayWidth, mDisplayHeight,
-                        mNativeWindow.get(), redSize, greenSize, blueSize, alphaSize, mOrientation,
-                        tr.getType(), getPageFlipCount(), mIsSecure, mPowerMode, mActiveConfig,
+                        mType, mHwcDisplayId, mLayerStack, mDisplayWidth, mDisplayHeight, window,
+                        redSize, greenSize, blueSize, alphaSize, mOrientation, tr.getType(),
+                        getPageFlipCount(), mIsSecure, mPowerMode, mActiveConfig,
                         mVisibleLayersSortedByZ.size());
     result.appendFormat("   v:[%d,%d,%d,%d], f:[%d,%d,%d,%d], s:[%d,%d,%d,%d],"
                         "transform:[[%0.3f,%0.3f,%0.3f][%0.3f,%0.3f,%0.3f][%0.3f,%0.3f,%0.3f]]\n",
@@ -636,6 +638,9 @@
                         mFrame.left, mFrame.top, mFrame.right, mFrame.bottom, mScissor.left,
                         mScissor.top, mScissor.right, mScissor.bottom, tr[0][0], tr[1][0], tr[2][0],
                         tr[0][1], tr[1][1], tr[2][1], tr[0][2], tr[1][2], tr[2][2]);
+    auto const surface = static_cast<Surface*>(window);
+    android_dataspace dataspace = surface->getBuffersDataSpace();
+    result.appendFormat("   dataspace: %s (%d)\n", dataspaceDetails(dataspace).c_str(), dataspace);
 
     String8 surfaceDump;
     mDisplaySurface->dumpAsString(surfaceDump);
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index e92565f..9435a18 100755
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -2501,7 +2501,7 @@
 
     const Layer::State& layerState(getDrawingState());
     const HWCInfo& hwcInfo = mHwcLayers.at(hwcId);
-    result.appendFormat("  %10u | ", layerState.z);
+    result.appendFormat("  %10d | ", layerState.z);
     result.appendFormat("%10s | ",
             to_string(getCompositionType(hwcId)).c_str());
     const Rect& frame = hwcInfo.displayFrame;
@@ -2625,14 +2625,53 @@
     return true;
 }
 
+bool Layer::reparentChild(const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle) {
+    if (newParentHandle == nullptr || childHandle == nullptr) {
+        return false;
+    }
+
+    auto handle = static_cast<Handle*>(newParentHandle.get());
+    sp<Layer> newParent = handle->owner.promote();
+    if (newParent == nullptr) {
+        ALOGE("Unable to promote Layer handle");
+        return false;
+    }
+
+    handle = static_cast<Handle*>(childHandle.get());
+    sp<Layer> child = handle->owner.promote();
+    if (child == nullptr) {
+        ALOGE("Unable to promote child Layer handle");
+        return false;
+    }
+
+    if (mCurrentChildren.indexOf(child) < 0) {
+        ALOGE("Child layer is not child of current layer");
+        return false;
+    }
+
+    sp<Client> parentClient(mClientRef.promote());
+    sp<Client> childClient(child->mClientRef.promote());
+    sp<Client> newParentClient(newParent->mClientRef.promote());
+
+    if (parentClient != childClient || childClient != newParentClient) {
+        ALOGE("Current layer, child layer, and new parent layer must have the same client");
+        return false;
+    }
+
+    newParent->addChild(child);
+    mCurrentChildren.remove(child);
+    return true;
+}
+
 bool Layer::detachChildren() {
     traverseInZOrder(LayerVector::StateSet::Drawing, [this](Layer* child) {
         if (child == this) {
             return;
         }
 
+        sp<Client> parentClient = mClientRef.promote();
         sp<Client> client(child->mClientRef.promote());
-        if (client != nullptr) {
+        if (client != nullptr && parentClient != client) {
             client->detachLayer(child);
         }
     });
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index f7b82e4..f94833b 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -241,6 +241,7 @@
     bool setOverrideScalingMode(int32_t overrideScalingMode);
     void setInfo(uint32_t type, uint32_t appId);
     bool reparentChildren(const sp<IBinder>& layer);
+    bool reparentChild(const sp<IBinder>& newParentHandle, const sp<IBinder>& childHandle);
     bool detachChildren();
 
     // If we have received a new buffer this frame, we will pass its surface
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 78af35b..cae4dea 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2788,7 +2788,14 @@
         if (parent == nullptr) {
             mCurrentState.layersSortedByZ.add(lbc);
         } else {
-            if (mCurrentState.layersSortedByZ.indexOf(parent) < 0) {
+            bool found = false;
+            mCurrentState.traverseInZOrder([&](Layer* layer) {
+                if (layer == parent.get()) {
+                    found = true;
+                }
+            });
+
+            if (!found) {
                 ALOGE("addClientLayer called with a removed parent");
                 return NAME_NOT_FOUND;
             }
@@ -3114,6 +3121,13 @@
             // We don't trigger a traversal here because if no other state is
             // changed, we don't want this to cause any more work
         }
+        // Always re-parent the children that explicitly requested to get
+        // re-parented before the general re-parent of all children.
+        if (what & layer_state_t::eReparentChild) {
+            if (layer->reparentChild(s.parentHandleForChild, s.childHandle)) {
+                flags |= eTransactionNeeded|eTraversalNeeded;
+            }
+        }
         if (what & layer_state_t::eReparentChildren) {
             if (layer->reparentChildren(s.reparentHandle)) {
                 flags |= eTransactionNeeded|eTraversalNeeded;
diff --git a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
index a92e1f9..71aa52d 100644
--- a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
+++ b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
@@ -2679,6 +2679,13 @@
             // We don't trigger a traversal here because if no other state is
             // changed, we don't want this to cause any more work
         }
+        // Always re-parent the children that explicitly requested to get
+        // re-parented before the general re-parent of all children.
+        if (what & layer_state_t::eReparentChild) {
+            if (layer->reparentChild(s.parentHandleForChild, s.childHandle)) {
+                flags |= eTransactionNeeded|eTraversalNeeded;
+            }
+        }
         if (what & layer_state_t::eReparentChildren) {
             if (layer->reparentChildren(s.reparentHandle)) {
                 flags |= eTransactionNeeded|eTraversalNeeded;
diff --git a/services/surfaceflinger/tests/Transaction_test.cpp b/services/surfaceflinger/tests/Transaction_test.cpp
index 4ce14f8..dea6503 100644
--- a/services/surfaceflinger/tests/Transaction_test.cpp
+++ b/services/surfaceflinger/tests/Transaction_test.cpp
@@ -990,7 +990,7 @@
     }
 }
 
-TEST_F(ChildLayerTest, DetachChildren) {
+TEST_F(ChildLayerTest, DetachChildrenSameClient) {
     SurfaceComposerClient::openGlobalTransaction();
     mChild->show();
     mChild->setPosition(10, 10);
@@ -1015,6 +1015,52 @@
     mChild->hide();
     SurfaceComposerClient::closeGlobalTransaction(true);
 
+    // Since the child has the same client as the parent, it will not get
+    // detached and will be hidden.
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        mCapture->expectFGColor(64, 64);
+        mCapture->expectFGColor(74, 74);
+        mCapture->expectFGColor(84, 84);
+    }
+}
+
+TEST_F(ChildLayerTest, DetachChildrenDifferentClient) {
+    sp<SurfaceComposerClient> mNewComposerClient = new SurfaceComposerClient;
+    sp<SurfaceControl> mChildNewClient = mNewComposerClient->createSurface(
+        String8("New Child Test Surface"), 10, 10, PIXEL_FORMAT_RGBA_8888,
+        0, mFGSurfaceControl.get());
+
+    ASSERT_TRUE(mChildNewClient != NULL);
+    ASSERT_TRUE(mChildNewClient->isValid());
+
+    fillSurfaceRGBA8(mChildNewClient, 200, 200, 200);
+
+    SurfaceComposerClient::openGlobalTransaction();
+    mChild->hide();
+    mChildNewClient->show();
+    mChildNewClient->setPosition(10, 10);
+    mFGSurfaceControl->setPosition(64, 64);
+    SurfaceComposerClient::closeGlobalTransaction(true);
+
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        // Top left of foreground must now be visible
+        mCapture->expectFGColor(64, 64);
+        // But 10 pixels in we should see the child surface
+        mCapture->expectChildColor(74, 74);
+        // And 10 more pixels we should be back to the foreground surface
+        mCapture->expectFGColor(84, 84);
+    }
+
+    SurfaceComposerClient::openGlobalTransaction();
+    mFGSurfaceControl->detachChildren();
+    SurfaceComposerClient::closeGlobalTransaction(true);
+
+    SurfaceComposerClient::openGlobalTransaction();
+    mChildNewClient->hide();
+    SurfaceComposerClient::closeGlobalTransaction(true);
+
     // Nothing should have changed.
     {
         ScreenCapture::captureScreen(&mCapture);
@@ -1123,4 +1169,48 @@
     fillSurfaceRGBA8(mFGSurfaceControl, 0, 255, 0);
 }
 
+TEST_F(ChildLayerTest, ReparentChild) {
+    SurfaceComposerClient::openGlobalTransaction();
+    mChild->show();
+    mChild->setPosition(10, 10);
+    mFGSurfaceControl->setPosition(64, 64);
+    SurfaceComposerClient::closeGlobalTransaction(true);
+
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        // Top left of foreground must now be visible
+        mCapture->expectFGColor(64, 64);
+        // But 10 pixels in we should see the child surface
+        mCapture->expectChildColor(74, 74);
+        // And 10 more pixels we should be back to the foreground surface
+        mCapture->expectFGColor(84, 84);
+    }
+    mFGSurfaceControl->reparentChild(mBGSurfaceControl->getHandle(), mChild->getHandle());
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        mCapture->expectFGColor(64, 64);
+        // In reparenting we should have exposed the entire foreground surface.
+        mCapture->expectFGColor(74, 74);
+        // And the child layer should now begin at 10, 10 (since the BG
+        // layer is at (0, 0)).
+        mCapture->expectBGColor(9, 9);
+        mCapture->expectChildColor(10, 10);
+    }
+}
+
+TEST_F(ChildLayerTest, NestedChildren) {
+    sp<SurfaceControl> grandchild = mComposerClient->createSurface(
+        String8("Grandchild surface"),
+        10, 10, PIXEL_FORMAT_RGBA_8888,
+        0, mChild.get());
+    fillSurfaceRGBA8(grandchild, 50, 50, 50);
+
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        // Expect the grandchild to begin at 64, 64 because it's a child of mChild layer
+        // which begins at 64, 64
+        mCapture->checkPixel(64, 64, 50, 50, 50);
+    }
+}
+
 }
diff --git a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp
index 60916f3..d97ffa3 100644
--- a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp
+++ b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.cpp
@@ -36,7 +36,6 @@
 #include <thread>
 
 constexpr Config NULL_DISPLAY_CONFIG = static_cast<Config>(0);
-constexpr Display DEFAULT_DISPLAY = static_cast<Display>(1);
 
 using namespace sftest;
 
@@ -168,7 +167,7 @@
     ALOGV("enableCallback");
     mCallbacksOn = enable;
     if (mCallbacksOn) {
-        mClient->onHotplug(DEFAULT_DISPLAY, IComposerCallback::Connection::CONNECTED);
+        mClient->onHotplug(PRIMARY_DISPLAY, IComposerCallback::Connection::CONNECTED);
     }
 }
 
@@ -507,7 +506,7 @@
         if (mSurfaceComposer != nullptr) {
             mSurfaceComposer->injectVSync(timestamp);
         } else {
-            mClient->onVsync(DEFAULT_DISPLAY, timestamp);
+            mClient->onVsync(PRIMARY_DISPLAY, timestamp);
         }
     }
 }
diff --git a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
index 294abb2..2a5a8ad 100644
--- a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
+++ b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
@@ -19,6 +19,9 @@
 #include "ComposerClient.h"
 #include "RenderState.h"
 
+// Needed for display type/ID enums
+#include <hardware/hwcomposer_defs.h>
+
 #include <utils/Condition.h>
 
 #include <chrono>
@@ -40,6 +43,13 @@
 
 namespace sftest {
 
+// NOTE: The ID's need to be exactly these. VR composer and parts of
+// the SurfaceFlinger assume the display IDs to have these values
+// despite the enum being documented as a display type.
+// TODO: Reference to actual documentation
+constexpr Display PRIMARY_DISPLAY = static_cast<Display>(HWC_DISPLAY_PRIMARY);
+constexpr Display EXTERNAL_DISPLAY = static_cast<Display>(HWC_DISPLAY_EXTERNAL);
+
 class FakeComposerClient : public ComposerBase {
 public:
     FakeComposerClient();
diff --git a/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp b/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
index 8902ede..9ac3331 100644
--- a/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
+++ b/services/surfaceflinger/tests/fakehwc/SFFakeHwc_test.cpp
@@ -168,17 +168,15 @@
     android::hardware::ProcessState::self()->startThreadPool();
     android::ProcessState::self()->startThreadPool();
 
-    EXPECT_CALL(*mMockComposer, getDisplayType(1, _))
+    EXPECT_CALL(*mMockComposer, getDisplayType(PRIMARY_DISPLAY, _))
             .WillOnce(DoAll(SetArgPointee<1>(IComposerClient::DisplayType::PHYSICAL),
                             Return(Error::NONE)));
-    // Seems to be doubled right now, once for display ID 1 and once for 0. This sounds fishy
-    // but encoding that here exactly.
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(1, 1, _, _))
-            .Times(5)
-            .WillRepeatedly(Invoke(mMockComposer, &MockComposerClient::getDisplayAttributeFake));
-    // TODO: Find out what code is generating the ID 0.
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(0, 1, _, _))
-            .Times(5)
+    // Primary display will be queried twice for all 5 attributes. One
+    // set of queries comes from the SurfaceFlinger proper an the
+    // other set from the VR composer.
+    // TODO: Is VR composer always present? Change to atLeast(5)?
+    EXPECT_CALL(*mMockComposer, getDisplayAttribute(PRIMARY_DISPLAY, 1, _, _))
+            .Times(2 * 5)
             .WillRepeatedly(Invoke(mMockComposer, &MockComposerClient::getDisplayAttributeFake));
 
     startSurfaceFlinger();
@@ -207,31 +205,32 @@
 TEST_F(DisplayTest, Hotplug) {
     ALOGD("DisplayTest::Hotplug");
 
-    EXPECT_CALL(*mMockComposer, getDisplayType(2, _))
+    EXPECT_CALL(*mMockComposer, getDisplayType(EXTERNAL_DISPLAY, _))
             .Times(2)
             .WillRepeatedly(DoAll(SetArgPointee<1>(IComposerClient::DisplayType::PHYSICAL),
                                   Return(Error::NONE)));
     // The attribute queries will get done twice. This is for defaults
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(2, 1, _, _))
+    EXPECT_CALL(*mMockComposer, getDisplayAttribute(EXTERNAL_DISPLAY, 1, _, _))
             .Times(2 * 3)
             .WillRepeatedly(Invoke(mMockComposer, &MockComposerClient::getDisplayAttributeFake));
     // ... and then special handling for dimensions. Specifying this
     // rules later means that gmock will try them first, i.e.,
     // ordering of width/height vs. the default implementation for
     // other queries is significant.
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(2, 1, IComposerClient::Attribute::WIDTH, _))
+    EXPECT_CALL(*mMockComposer,
+                getDisplayAttribute(EXTERNAL_DISPLAY, 1, IComposerClient::Attribute::WIDTH, _))
             .Times(2)
             .WillRepeatedly(DoAll(SetArgPointee<3>(400), Return(Error::NONE)));
 
-    EXPECT_CALL(*mMockComposer, getDisplayAttribute(2, 1, IComposerClient::Attribute::HEIGHT, _))
+    EXPECT_CALL(*mMockComposer,
+                getDisplayAttribute(EXTERNAL_DISPLAY, 1, IComposerClient::Attribute::HEIGHT, _))
             .Times(2)
             .WillRepeatedly(DoAll(SetArgPointee<3>(200), Return(Error::NONE)));
 
     // TODO: Width and height queries are not actually called. Display
     // info returns dimensions 0x0 in display info. Why?
 
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::CONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::CONNECTED);
 
     {
         sp<android::IBinder> display(
@@ -257,13 +256,11 @@
         }
     }
 
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::DISCONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::DISCONNECTED);
 
     mMockComposer->clearFrames();
 
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::CONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::CONNECTED);
 
     {
         sp<android::IBinder> display(
@@ -288,8 +285,7 @@
             ASSERT_EQ(NO_ERROR, surfaceControl->show());
         }
     }
-    mMockComposer->hotplugDisplay(static_cast<Display>(2),
-                                  IComposerCallback::Connection::DISCONNECTED);
+    mMockComposer->hotplugDisplay(EXTERNAL_DISPLAY, IComposerCallback::Connection::DISCONNECTED);
 }
 
 ////////////////////////////////////////////////
@@ -664,7 +660,7 @@
              {{0.f, 1.f, 1.f, 0.f},     HWC_TRANSFORM_FLIP_H_ROT_90,    {64, 64, 128, 128}},
              {{0.f, 1.f, 1.f, 0.f},     HWC_TRANSFORM_FLIP_V_ROT_90,    {64, 64, 128, 128}}};
     // clang-format on
-    constexpr int TEST_COUNT = sizeof(MATRIX_TESTS)/sizeof(matrixTestData);
+    constexpr int TEST_COUNT = sizeof(MATRIX_TESTS) / sizeof(matrixTestData);
 
     for (int i = 0; i < TEST_COUNT; i++) {
         // TODO: How to leverage the HWC2 stringifiers?
diff --git a/services/surfaceflinger/tests/hwc2/Android.mk b/services/surfaceflinger/tests/hwc2/Android.mk
index 203ced5..6d20349 100644
--- a/services/surfaceflinger/tests/hwc2/Android.mk
+++ b/services/surfaceflinger/tests/hwc2/Android.mk
@@ -36,7 +36,9 @@
     libui \
     libgui \
     liblog \
-    libsync
+    libsync \
+    libskia \
+    android.hardware.graphics.common@1.0
 LOCAL_STATIC_LIBRARIES := \
     libbase \
     libadf \
@@ -49,6 +51,7 @@
     Hwc2TestLayers.cpp \
     Hwc2TestBuffer.cpp \
     Hwc2TestClientTarget.cpp \
-    Hwc2TestVirtualDisplay.cpp
+    Hwc2TestVirtualDisplay.cpp \
+    Hwc2TestPixelComparator.cpp
 
 include $(BUILD_NATIVE_TEST)
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp b/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp
index 4055527..4878c14 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2Test.cpp
@@ -1775,6 +1775,145 @@
         }
     }
 
+    void createAndPresentVirtualDisplay(size_t layerCnt,
+            Hwc2TestCoverage coverage,
+            const std::unordered_map<Hwc2TestPropertyName, Hwc2TestCoverage>&
+            coverageExceptions)
+    {
+        Hwc2TestVirtualDisplay testVirtualDisplay(coverage);
+        hwc2_display_t display;
+        android_pixel_format_t desiredFormat = HAL_PIXEL_FORMAT_RGBA_8888;
+
+        do {
+            // Items dependent on the display dimensions
+            hwc2_error_t err = HWC2_ERROR_NONE;
+            const UnsignedArea& dimension =
+                    testVirtualDisplay.getDisplayDimension();
+            ASSERT_NO_FATAL_FAILURE(createVirtualDisplay(dimension.width,
+                    dimension.height, &desiredFormat, &display, &err));
+            ASSERT_TRUE(err == HWC2_ERROR_NONE)
+                    << "Cannot allocate virtual display";
+
+            ASSERT_NO_FATAL_FAILURE(setPowerMode(display, HWC2_POWER_MODE_ON));
+            ASSERT_NO_FATAL_FAILURE(enableVsync(display));
+
+            std::vector<hwc2_config_t> configs;
+            ASSERT_NO_FATAL_FAILURE(getDisplayConfigs(display, &configs));
+
+            for (auto config : configs) {
+                ASSERT_NO_FATAL_FAILURE(setActiveConfig(display, config));
+
+                Area displayArea;
+                ASSERT_NO_FATAL_FAILURE(getActiveDisplayArea(display,
+                        &displayArea));
+
+                std::vector<hwc2_layer_t> layers;
+                ASSERT_NO_FATAL_FAILURE(createLayers(display, &layers,
+                        layerCnt));
+                Hwc2TestLayers testLayers(layers, coverage, displayArea,
+                        coverageExceptions);
+
+                /*
+                 * Layouts that do not cover an entire virtual display will
+                 * cause undefined behavior.
+                 * Enable optimizeLayouts to avoid this.
+                 */
+                testLayers.optimizeLayouts();
+                do {
+                    // Items dependent on the testLayers properties
+                    std::set<hwc2_layer_t> clientLayers;
+                    std::set<hwc2_layer_t> clearLayers;
+                    uint32_t numTypes, numRequests;
+                    bool hasChanges, skip;
+                    bool flipClientTarget;
+                    int32_t presentFence;
+                    Hwc2TestClientTarget testClientTarget;
+                    buffer_handle_t outputBufferHandle;
+                    android::base::unique_fd outputBufferReleaseFence;
+
+                    ASSERT_NO_FATAL_FAILURE(setLayerProperties(display, layers,
+                            &testLayers, &skip));
+
+                    if (skip)
+                        continue;
+
+                    ASSERT_NO_FATAL_FAILURE(validateDisplay(display, &numTypes,
+                            &numRequests, &hasChanges));
+
+                    if (hasChanges)
+                        EXPECT_LE(numTypes, static_cast<uint32_t>(layers.size()))
+                                << "wrong number of requests";
+
+                    ASSERT_NO_FATAL_FAILURE(handleCompositionChanges(display,
+                            testLayers, layers, numTypes, &clientLayers));
+
+                    ASSERT_NO_FATAL_FAILURE(handleRequests(display, layers,
+                            numRequests, &clearLayers, &flipClientTarget));
+                    ASSERT_NO_FATAL_FAILURE(setClientTarget(display,
+                            &testClientTarget, testLayers, clientLayers,
+                            clearLayers, flipClientTarget, displayArea));
+                    ASSERT_NO_FATAL_FAILURE(acceptDisplayChanges(display));
+
+                    ASSERT_EQ(testVirtualDisplay.getOutputBuffer(
+                            &outputBufferHandle, &outputBufferReleaseFence), 0);
+                    ASSERT_NO_FATAL_FAILURE(setOutputBuffer(display,
+                            outputBufferHandle, outputBufferReleaseFence));
+
+                    EXPECT_NO_FATAL_FAILURE(presentDisplay(display,
+                            &presentFence));
+                    ASSERT_NO_FATAL_FAILURE(closeFences(display, presentFence));
+
+                    ASSERT_EQ(testVirtualDisplay.verifyOutputBuffer(&testLayers,
+                            &layers, &clearLayers), 0);
+
+                    /*
+                     * Upscaling the image causes minor pixel differences.
+                     * Work around this by using some threshold.
+                     *
+                     * Fail test if we are off by more than 1% of our
+                     * pixels.
+                     */
+                    ComparatorResult& comparatorResult = ComparatorResult::get();
+                    int threshold = (dimension.width * dimension.height) / 100;
+                    double diffPercent = (comparatorResult.getDifferentPixelCount() * 100.0) /
+                            (dimension.width * dimension.height);
+
+                    if (comparatorResult.getDifferentPixelCount() != 0)
+                        EXPECT_TRUE(false)
+                                << comparatorResult.getDifferentPixelCount() << " pixels ("
+                                << diffPercent << "%) are different.";
+
+                    if (comparatorResult.getDifferentPixelCount() > threshold) {
+                        EXPECT_TRUE(false)
+                                << "Mismatched pixel count exceeds threshold. "
+                                << "Writing buffers to file.";
+
+                        const ::testing::TestInfo* const test_info =
+                                ::testing::UnitTest::GetInstance()
+                                ->current_test_info();
+
+                        EXPECT_EQ(testVirtualDisplay.writeBuffersToFile(
+                                test_info->name()), 0)
+                                << "Failed to write buffers.";
+                    }
+
+                    ASSERT_LE(comparatorResult.getDifferentPixelCount(), threshold)
+                            << comparatorResult.getDifferentPixelCount() << " pixels ("
+                            << diffPercent << "%) are different. "
+                            << "Exceeds 1% threshold, terminating test. "
+                            << "Test case: " << testLayers.dump();
+
+                } while (testLayers.advance());
+
+                ASSERT_NO_FATAL_FAILURE(destroyLayers(display,
+                        std::move(layers)));
+            }
+            ASSERT_NO_FATAL_FAILURE(disableVsync(display));
+            ASSERT_NO_FATAL_FAILURE(setPowerMode(display, HWC2_POWER_MODE_OFF));
+            ASSERT_NO_FATAL_FAILURE(destroyVirtualDisplay(display));
+        } while (testVirtualDisplay.advance());
+    }
+
     hwc2_device_t* mHwc2Device = nullptr;
 
     enum class Hwc2TestHotplugStatus {
@@ -4479,7 +4618,7 @@
                 buffer_handle_t handle;
                 android::base::unique_fd acquireFence;
 
-                if (testVirtualDisplay->getBuffer(&handle, &acquireFence) >= 0)
+                if (testVirtualDisplay->getOutputBuffer(&handle, &acquireFence) >= 0)
                     EXPECT_NO_FATAL_FAILURE(test->setOutputBuffer(display,
                             handle, acquireFence));
             }));
@@ -4499,7 +4638,7 @@
 
                 ASSERT_NO_FATAL_FAILURE(test->getBadDisplay(&badDisplay));
 
-                if (testVirtualDisplay->getBuffer(&handle, &acquireFence) < 0)
+                if (testVirtualDisplay->getOutputBuffer(&handle, &acquireFence) < 0)
                     return;
 
                 ASSERT_NO_FATAL_FAILURE(test->setOutputBuffer(badDisplay,
@@ -4539,7 +4678,7 @@
             android::base::unique_fd acquireFence;
             hwc2_error_t err = HWC2_ERROR_NONE;
 
-            if (testVirtualDisplay.getBuffer(&handle, &acquireFence) < 0)
+            if (testVirtualDisplay.getOutputBuffer(&handle, &acquireFence) < 0)
                 continue;
 
             ASSERT_NO_FATAL_FAILURE(setOutputBuffer(display, handle,
@@ -4557,3 +4696,74 @@
 
     ASSERT_NO_FATAL_FAILURE(dump(&buffer));
 }
+
+/*
+ * TODO(b/64724708): Hwc2TestPropertyName::BufferArea MUST be default for all
+ * virtual display tests as we don't handle this case correctly.
+ *
+ * Only default dataspace is supported in our drawing code.
+ */
+const std::unordered_map<Hwc2TestPropertyName, Hwc2TestCoverage>
+        virtualDisplayExceptions =
+        {{Hwc2TestPropertyName::BufferArea, Hwc2TestCoverage::Default},
+        {Hwc2TestPropertyName::Dataspace, Hwc2TestCoverage::Default}};
+
+/* TESTCASE: Tests that the HWC2 can present 1 layer with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_1)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 1;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 1 layer with basic coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_basic_1)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Basic;
+    const size_t layerCnt = 1;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 2 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_2)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 2;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 3 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_3)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 3;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 4 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_4)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 4;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
+
+/* TESTCASE: Tests that the HWC2 can present 5 layers with default coverage on a
+ * virtual display. */
+TEST_F(Hwc2Test, PRESENT_VIRTUAL_DISPLAY_default_5)
+{
+    Hwc2TestCoverage coverage = Hwc2TestCoverage::Default;
+    const size_t layerCnt = 5;
+    ASSERT_NO_FATAL_FAILURE(createAndPresentVirtualDisplay(layerCnt, coverage,
+            virtualDisplayExceptions));
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp
index 1d3a1d3..6484562 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.cpp
@@ -23,14 +23,17 @@
 #include <gui/BufferItemConsumer.h>
 
 #include <ui/GraphicBuffer.h>
+#include <android/hardware/graphics/common/1.0/types.h>
 #include <math/vec4.h>
 
 #include <GLES3/gl3.h>
-
+#include <SkImageEncoder.h>
+#include <SkStream.h>
 #include "Hwc2TestBuffer.h"
 #include "Hwc2TestLayers.h"
 
 using namespace android;
+using android::hardware::graphics::common::V1_0::BufferUsage;
 
 /* Returns a fence from egl */
 typedef void (*FenceCallback)(int32_t fence, void* callbackArgs);
@@ -396,8 +399,9 @@
 {
     /* Create new graphic buffer with correct dimensions */
     mGraphicBuffer = new GraphicBuffer(mBufferArea.width, mBufferArea.height,
-            mFormat, GRALLOC_USAGE_SW_READ_OFTEN | GRALLOC_USAGE_HW_RENDER,
-            "hwc2_test_buffer");
+            mFormat, BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN |
+            BufferUsage::COMPOSER_OVERLAY, "hwc2_test_buffer");
+
     int ret = mGraphicBuffer->initCheck();
     if (ret) {
         return ret;
@@ -408,7 +412,8 @@
 
     /* Locks the buffer for writing */
     uint8_t* img;
-    mGraphicBuffer->lock(GRALLOC_USAGE_SW_WRITE_OFTEN, (void**)(&img));
+    mGraphicBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_WRITE_OFTEN),
+            (void**)(&img));
 
     uint32_t stride = mGraphicBuffer->getStride();
 
@@ -458,31 +463,22 @@
 
 Hwc2TestClientTargetBuffer::~Hwc2TestClientTargetBuffer() { }
 
-/* Generates a client target buffer using the layers assigned for client
- * composition. Takes into account the individual layer properties such as
+/* Generates a buffer from layersToDraw.
+ * Takes into account the individual layer properties such as
  * transform, blend mode, source crop, etc. */
-int Hwc2TestClientTargetBuffer::get(buffer_handle_t* outHandle,
-        int32_t* outFence, const Area& bufferArea,
+static void compositeBufferFromLayers(
+        const android::sp<android::GraphicBuffer>& graphicBuffer,
+        android_pixel_format_t format, const Area& bufferArea,
         const Hwc2TestLayers* testLayers,
-        const std::set<hwc2_layer_t>* clientLayers,
+        const std::set<hwc2_layer_t>* layersToDraw,
         const std::set<hwc2_layer_t>* clearLayers)
 {
-    /* Create new graphic buffer with correct dimensions */
-    mGraphicBuffer = new GraphicBuffer(bufferArea.width, bufferArea.height,
-            mFormat, GRALLOC_USAGE_SW_READ_OFTEN | GRALLOC_USAGE_HW_RENDER,
-            "hwc2_test_buffer");
-    int ret = mGraphicBuffer->initCheck();
-    if (ret) {
-        return ret;
-    }
-    if (!mGraphicBuffer->handle) {
-        return -EINVAL;
-    }
-
+    /* Locks the buffer for writing */
     uint8_t* img;
-    mGraphicBuffer->lock(GRALLOC_USAGE_SW_WRITE_OFTEN, (void**)(&img));
+    graphicBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_WRITE_OFTEN),
+            (void**)(&img));
 
-    uint32_t stride = mGraphicBuffer->getStride();
+    uint32_t stride = graphicBuffer->getStride();
 
     float bWDiv3 = bufferArea.width / 3;
     float bW2Div3 = bufferArea.width * 2 / 3;
@@ -497,10 +493,10 @@
             uint8_t r = 0, g = 0, b = 0;
             float a = 0.0f;
 
-            /* Cycle through each client layer from back to front and
+            /* Cycle through each layer from back to front and
              * update the pixel color. */
-            for (auto layer = clientLayers->rbegin();
-                    layer != clientLayers->rend(); ++layer) {
+            for (auto layer = layersToDraw->rbegin();
+                    layer != layersToDraw->rend(); ++layer) {
 
                 const hwc_rect_t df = testLayers->getDisplayFrame(*layer);
 
@@ -570,8 +566,8 @@
                      * (100x50) at the end of the transformation. */
                     if (transform & HWC_TRANSFORM_ROT_90) {
                         float tmp = xPos;
-                        xPos = -yPos * dfW / dfH;
-                        yPos = tmp * dfH / dfW;
+                        xPos = yPos * dfW / dfH;
+                        yPos = -tmp * dfH / dfW;
                     }
 
                     /* Change origin back to the top left corner of the
@@ -682,14 +678,114 @@
             }
 
             /* Set the pixel color */
-            setColor(x, y, mFormat, stride, img, r, g, b, a * 255);
+            setColor(x, y, format, stride, img, r, g, b, a * 255);
         }
     }
 
-    mGraphicBuffer->unlock();
+    graphicBuffer->unlock();
+}
+
+/* Generates a client target buffer using the layers assigned for client
+ * composition. Takes into account the individual layer properties such as
+ * transform, blend mode, source crop, etc. */
+int Hwc2TestClientTargetBuffer::get(buffer_handle_t* outHandle,
+        int32_t* outFence, const Area& bufferArea,
+        const Hwc2TestLayers* testLayers,
+        const std::set<hwc2_layer_t>* clientLayers,
+        const std::set<hwc2_layer_t>* clearLayers)
+{
+    /* Create new graphic buffer with correct dimensions */
+    mGraphicBuffer = new GraphicBuffer(bufferArea.width, bufferArea.height,
+            mFormat, BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN |
+            BufferUsage::COMPOSER_OVERLAY, "hwc2_test_buffer");
+
+    int ret = mGraphicBuffer->initCheck();
+    if (ret)
+        return ret;
+
+    if (!mGraphicBuffer->handle)
+        return -EINVAL;
+
+    compositeBufferFromLayers(mGraphicBuffer, mFormat, bufferArea, testLayers,
+            clientLayers, clearLayers);
 
     *outFence = mFenceGenerator->get();
     *outHandle = mGraphicBuffer->handle;
 
     return 0;
 }
+
+void Hwc2TestVirtualBuffer::updateBufferArea(const Area& bufferArea)
+{
+    mBufferArea.width = bufferArea.width;
+    mBufferArea.height = bufferArea.height;
+}
+
+bool Hwc2TestVirtualBuffer::writeBufferToFile(std::string path)
+{
+    SkFILEWStream file(path.c_str());
+    const SkImageInfo info = SkImageInfo::Make(mBufferArea.width,
+            mBufferArea.height, SkColorType::kRGBA_8888_SkColorType,
+            SkAlphaType::kPremul_SkAlphaType);
+
+    uint8_t* img;
+    mGraphicBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_WRITE_OFTEN),
+            (void**)(&img));
+
+    SkPixmap pixmap(info, img, mGraphicBuffer->getStride());
+    bool result = file.isValid() && SkEncodeImage(&file, pixmap,
+            SkEncodedImageFormat::kPNG, 100);
+
+    mGraphicBuffer->unlock();
+    return result;
+}
+
+/* Generates a buffer that holds the expected result of compositing all of our
+ * layers */
+int Hwc2TestExpectedBuffer::generateExpectedBuffer(
+        const Hwc2TestLayers* testLayers,
+        const std::vector<hwc2_layer_t>* allLayers,
+        const std::set<hwc2_layer_t>* clearLayers)
+{
+    mGraphicBuffer = new GraphicBuffer(mBufferArea.width, mBufferArea.height,
+            mFormat, BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN,
+            "hwc2_test_buffer");
+
+    int ret = mGraphicBuffer->initCheck();
+    if (ret)
+        return ret;
+
+    if (!mGraphicBuffer->handle)
+        return -EINVAL;
+
+    const std::set<hwc2_layer_t> allLayerSet(allLayers->begin(),
+            allLayers->end());
+
+    compositeBufferFromLayers(mGraphicBuffer, mFormat, mBufferArea, testLayers,
+            &allLayerSet, clearLayers);
+
+    return 0;
+}
+
+int Hwc2TestOutputBuffer::getOutputBuffer(buffer_handle_t* outHandle,
+        int32_t* outFence)
+{
+    if (mBufferArea.width == -1 || mBufferArea.height == -1)
+        return -EINVAL;
+
+    mGraphicBuffer = new GraphicBuffer(mBufferArea.width, mBufferArea.height,
+            mFormat, BufferUsage::CPU_READ_OFTEN |
+            BufferUsage::GPU_RENDER_TARGET, "hwc2_test_buffer");
+
+    int ret = mGraphicBuffer->initCheck();
+    if (ret)
+        return ret;
+
+    if (!mGraphicBuffer->handle)
+        return -EINVAL;
+
+    *outFence = -1;
+    *outHandle = mGraphicBuffer->handle;
+
+    return 0;
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h
index b2b3a66..fd54fef 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestBuffer.h
@@ -71,4 +71,38 @@
     const android_pixel_format_t mFormat = HAL_PIXEL_FORMAT_RGBA_8888;
 };
 
+
+class Hwc2TestVirtualBuffer {
+public:
+    void updateBufferArea(const Area& bufferArea);
+
+    bool writeBufferToFile(std::string path);
+
+    android::sp<android::GraphicBuffer>& graphicBuffer()
+    {
+        return mGraphicBuffer;
+    }
+
+protected:
+    android::sp<android::GraphicBuffer> mGraphicBuffer;
+
+    Area mBufferArea = {-1, -1};
+
+    const android_pixel_format_t mFormat = HAL_PIXEL_FORMAT_RGBA_8888;
+};
+
+
+class Hwc2TestExpectedBuffer : public Hwc2TestVirtualBuffer {
+public:
+    int generateExpectedBuffer(const Hwc2TestLayers* testLayers,
+            const std::vector<hwc2_layer_t>* allLayers,
+            const std::set<hwc2_layer_t>* clearLayers);
+};
+
+
+class Hwc2TestOutputBuffer : public Hwc2TestVirtualBuffer {
+public:
+    int getOutputBuffer(buffer_handle_t* outHandle, int32_t* outFence);
+};
+
 #endif /* ifndef _HWC2_TEST_BUFFER_H */
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.cpp
new file mode 100644
index 0000000..904b927
--- /dev/null
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.cpp
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sstream>
+#include <android/hardware/graphics/common/1.0/types.h>
+
+#include "Hwc2TestPixelComparator.h"
+
+using android::hardware::graphics::common::V1_0::BufferUsage;
+
+uint32_t ComparatorResult::getPixel(int32_t x, int32_t y, uint32_t stride,
+        uint8_t* img) const
+{
+    uint32_t r = img[(y * stride + x) * 4 + 0];
+    uint32_t g = img[(y * stride + x) * 4 + 1];
+    uint32_t b = img[(y * stride + x) * 4 + 2];
+    uint32_t a = img[(y * stride + x) * 4 + 3];
+
+    uint32_t pixel = 0;
+    pixel |= r;
+    pixel |= g << 8;
+    pixel |= b << 16;
+    pixel |= a << 24;
+    return pixel;
+}
+
+void ComparatorResult::CompareBuffers(
+        android::sp<android::GraphicBuffer>& resultBuffer,
+        android::sp<android::GraphicBuffer>& expectedBuffer)
+{
+    uint8_t* resultBufferImg;
+    uint8_t* expectedBufferImg;
+    resultBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_READ_OFTEN),
+            (void**)(&resultBufferImg));
+
+    expectedBuffer->lock(static_cast<uint32_t>(BufferUsage::CPU_READ_OFTEN),
+            (void**)(&expectedBufferImg));
+    mComparisons.clear();
+    int32_t mDifferentPixelCount = 0;
+    int32_t mBlankPixelCount = 0;
+
+    for (uint32_t y = 0; y < resultBuffer->getHeight(); y++) {
+        for (uint32_t x = 0; x < resultBuffer->getWidth(); x++) {
+            uint32_t result = getPixel(x, y, resultBuffer->getStride(),
+                    resultBufferImg);
+            uint32_t expected = getPixel(x, y, expectedBuffer->getStride(),
+                    expectedBufferImg);
+
+            if (result == 0)
+                mBlankPixelCount++;
+
+            if (result != expected)
+                mDifferentPixelCount++;
+
+            mComparisons.emplace_back(std::make_tuple(x, y, result, expected));
+        }
+    }
+    resultBuffer->unlock();
+    expectedBuffer->unlock();
+}
+
+std::string ComparatorResult::pixelDiff(uint32_t x, uint32_t y,
+        uint32_t resultPixel, uint32_t expectedPixel) const
+{
+    uint32_t resultAlpha = (resultPixel >> 24) & 0xFF;
+    uint32_t resultBlue = (resultPixel >> 16) & 0xFF;
+    uint32_t resultGreen = (resultPixel >> 8) & 0xFF;
+    uint32_t resultRed = resultPixel & 0xFF;
+
+    uint32_t expectedAlpha = (expectedPixel >> 24) & 0xFF;
+    uint32_t expectedBlue = (expectedPixel >> 16) & 0xFF;
+    uint32_t expectedGreen = (expectedPixel >> 8) & 0xFF;
+    uint32_t expectedRed = expectedPixel & 0xFF;
+
+    std::ostringstream stream;
+
+    stream << "x: " << x << " y: " << y << std::endl;
+    stream << std::hex;
+    stream << "Result pixel:   " << resultRed << "|" << resultGreen << "|"
+           << resultBlue << "|" << resultAlpha << std::endl;
+
+    stream << "Expected pixel: " << expectedRed << "|" << expectedGreen << "|"
+           << expectedBlue << "|" << expectedAlpha << std::endl;
+
+    return stream.str();
+}
+
+std::string ComparatorResult::dumpComparison() const
+{
+    std::ostringstream stream;
+    stream << "Number of different pixels: " << mDifferentPixelCount;
+
+    for (const auto& comparison : mComparisons) {
+        if (std::get<2>(comparison) != std::get<3>(comparison))
+            stream << pixelDiff(std::get<0>(comparison),
+                    std::get<1>(comparison), std::get<2>(comparison),
+                    std::get<3>(comparison));
+    }
+    return stream.str();
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.h b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.h
new file mode 100644
index 0000000..55fa936
--- /dev/null
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestPixelComparator.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef _HWC2_TEST_PIXEL_COMPARATOR_H
+#define _HWC2_TEST_PIXEL_COMPARATOR_H
+
+#include <ui/GraphicBuffer.h>
+#include <cstdint>
+#include <string>
+#include <utility>
+#include <vector>
+
+class ComparatorResult {
+public:
+    static ComparatorResult& get()
+    {
+        static ComparatorResult instance;
+        return instance;
+    }
+
+    void CompareBuffers(android::sp<android::GraphicBuffer>& resultBuffer,
+            android::sp<android::GraphicBuffer>& expectedBuffer);
+
+    std::string dumpComparison() const;
+
+    ComparatorResult(const ComparatorResult&) = delete;
+    ComparatorResult(ComparatorResult&&) = delete;
+    ComparatorResult& operator=(ComparatorResult const&) = delete;
+    ComparatorResult& operator=(ComparatorResult&&) = delete;
+
+    int32_t getDifferentPixelCount() const { return mDifferentPixelCount; }
+    int32_t getBlankPixelCount() const { return mBlankPixelCount; }
+
+private:
+    ComparatorResult() = default;
+    uint32_t getPixel(int32_t x, int32_t y, uint32_t stride, uint8_t* img) const;
+    std::string pixelDiff(uint32_t x, uint32_t y, uint32_t resultPixel,
+            uint32_t expectedPixel) const;
+
+    int32_t mDifferentPixelCount;
+    int32_t mBlankPixelCount;
+    /* std::tuple<X coordinate, Y coordinate, resultPixel, expectedPixel> */
+    std::vector<std::tuple<uint32_t, uint32_t, uint32_t, uint32_t>>
+            mComparisons;
+};
+
+#endif /* ifndef _HWC2_TEST_PIXEL_COMPARATOR_H */
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp
index b5522de..5b3bbeb 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.cpp
@@ -335,9 +335,9 @@
     return dmp.str();
 }
 
-void Hwc2TestDisplayDimension::setDependent(Hwc2TestBuffer* buffer)
+void Hwc2TestDisplayDimension::setDependent(Hwc2TestVirtualBuffer* buffer)
 {
-    mBuffer = buffer;
+    mBuffers.insert(buffer);
     updateDependents();
 }
 
@@ -345,8 +345,8 @@
 {
     const UnsignedArea& curr = get();
 
-    if (mBuffer)
-        mBuffer->updateBufferArea({static_cast<int32_t>(curr.width),
+    for (Hwc2TestVirtualBuffer* buffer : mBuffers)
+        buffer->updateBufferArea({static_cast<int32_t>(curr.width),
                 static_cast<int32_t>(curr.height)});
 }
 
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h
index c2029ab..cb811e0 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestProperties.h
@@ -243,6 +243,7 @@
     static const std::array<bool, 6> mCompositionSupport;
 };
 
+class Hwc2TestVirtualBuffer;
 
 class Hwc2TestDisplayDimension : public Hwc2TestProperty<UnsignedArea> {
 public:
@@ -250,12 +251,12 @@
 
     std::string dump() const;
 
-    void setDependent(Hwc2TestBuffer* buffer);
+    void setDependent(Hwc2TestVirtualBuffer* buffer);
 
 private:
     void updateDependents();
 
-    Hwc2TestBuffer* mBuffer;
+    std::set<Hwc2TestVirtualBuffer*> mBuffers;
 
     static const std::vector<UnsignedArea> mDefaultDisplayDimensions;
     static const std::vector<UnsignedArea> mBasicDisplayDimensions;
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp
index d0fbc0b..e6cceb8 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.cpp
@@ -15,14 +15,18 @@
  */
 
 #include <sstream>
+#include <sys/stat.h>
 
 #include "Hwc2TestVirtualDisplay.h"
 
+#define DIR_NAME "images"
+
 Hwc2TestVirtualDisplay::Hwc2TestVirtualDisplay(
         Hwc2TestCoverage coverage)
     : mDisplayDimension(coverage)
 {
-    mDisplayDimension.setDependent(&mBuffer);
+    mDisplayDimension.setDependent(&mOutputBuffer);
+    mDisplayDimension.setDependent(&mExpectedBuffer);
 }
 
 std::string Hwc2TestVirtualDisplay::dump() const
@@ -36,11 +40,11 @@
     return dmp.str();
 }
 
-int Hwc2TestVirtualDisplay::getBuffer(buffer_handle_t* outHandle,
+int Hwc2TestVirtualDisplay::getOutputBuffer(buffer_handle_t* outHandle,
         android::base::unique_fd* outAcquireFence)
 {
     int32_t acquireFence;
-    int ret = mBuffer.get(outHandle, &acquireFence);
+    int ret = mOutputBuffer.getOutputBuffer(outHandle, &acquireFence);
     outAcquireFence->reset(acquireFence);
     return ret;
 }
@@ -59,3 +63,36 @@
 {
     return mDisplayDimension.get();
 }
+
+int Hwc2TestVirtualDisplay::verifyOutputBuffer(const Hwc2TestLayers* testLayers,
+        const std::vector<hwc2_layer_t>* allLayers,
+        const std::set<hwc2_layer_t>* clearLayers)
+{
+    int ret = mExpectedBuffer.generateExpectedBuffer(testLayers, allLayers,
+            clearLayers);
+    if (ret)
+        return ret;
+
+    ComparatorResult::get().CompareBuffers(mOutputBuffer.graphicBuffer(),
+        mExpectedBuffer.graphicBuffer());
+
+    return 0;
+}
+
+int Hwc2TestVirtualDisplay::writeBuffersToFile(std::string name)
+{
+    std::ostringstream expectedPath;
+    std::ostringstream resultPath;
+    int ret = mkdir(DIR_NAME, DEFFILEMODE);
+    if (ret && errno != EEXIST)
+        return ret;
+
+    expectedPath << DIR_NAME << "/expected-" << name << ".png";
+    resultPath << DIR_NAME << "/result-" << name << ".png";
+
+    if (!mExpectedBuffer.writeBufferToFile(expectedPath.str()) ||
+            !mOutputBuffer.writeBufferToFile(resultPath.str()))
+        return -1;
+
+    return 0;
+}
diff --git a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h
index 09420ef..10c8ef0 100644
--- a/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h
+++ b/services/surfaceflinger/tests/hwc2/Hwc2TestVirtualDisplay.h
@@ -18,6 +18,7 @@
 #define _HWC2_TEST_VIRTUAL_DISPLAY_H
 
 #include "Hwc2TestBuffer.h"
+#include "Hwc2TestPixelComparator.h"
 #include "Hwc2TestProperties.h"
 
 #define HWC2_INCLUDE_STRINGIFICATION
@@ -32,17 +33,22 @@
 
     std::string dump() const;
 
-    int getBuffer(buffer_handle_t* outHandle,
+    int getOutputBuffer(buffer_handle_t* outHandle,
             android::base::unique_fd* outAcquireFence);
 
+    int verifyOutputBuffer(const Hwc2TestLayers* testLayers,
+            const std::vector<hwc2_layer_t>* allLayers,
+            const std::set<hwc2_layer_t>* clearLayers);
+
+    int writeBuffersToFile(std::string name);
     void reset();
     bool advance();
 
     UnsignedArea getDisplayDimension() const;
 
 private:
-    Hwc2TestBuffer mBuffer;
-
+    Hwc2TestOutputBuffer mOutputBuffer;
+    Hwc2TestExpectedBuffer mExpectedBuffer;
     Hwc2TestDisplayDimension mDisplayDimension;
 };