diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index e5d23d0..4226e9a 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -165,6 +165,7 @@
         "Scheduler/PhaseOffsets.cpp",
         "Scheduler/Scheduler.cpp",
         "Scheduler/SchedulerUtils.cpp",
+        "Scheduler/VSyncDispatch.cpp",
         "Scheduler/VSyncModulator.cpp",
         "StartPropertySetThread.cpp",
         "SurfaceFlinger.cpp",
diff --git a/services/surfaceflinger/Scheduler/TimeKeeper.h b/services/surfaceflinger/Scheduler/TimeKeeper.h
new file mode 100644
index 0000000..699cd50
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/TimeKeeper.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2019 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.
+ */
+
+#pragma once
+
+#include <utils/Timers.h>
+#include <functional>
+
+namespace android::scheduler {
+
+/*
+ * TimeKeeper is the interface for a single-shot timer primitive.
+ */
+class TimeKeeper {
+public:
+    virtual ~TimeKeeper();
+
+    /*
+     * Arms callback to fired in time nanoseconds.
+     * There is only one timer, and subsequent calls will reset the callback function and the time.
+     */
+    virtual void alarmIn(std::function<void()> const& callback, nsecs_t time) = 0;
+
+    /*
+     * Cancels an existing pending callback
+     */
+    virtual void alarmCancel() = 0;
+
+    /*
+     * Returns the SYSTEM_TIME_MONOTONIC, used by testing infra to stub time.
+     */
+    virtual nsecs_t now() const = 0;
+
+protected:
+    TimeKeeper(TimeKeeper const&) = delete;
+    TimeKeeper& operator=(TimeKeeper const&) = delete;
+    TimeKeeper() = default;
+};
+
+} // namespace android::scheduler
diff --git a/services/surfaceflinger/Scheduler/VSyncDispatch.cpp b/services/surfaceflinger/Scheduler/VSyncDispatch.cpp
new file mode 100644
index 0000000..c9b2e77
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/VSyncDispatch.cpp
@@ -0,0 +1,285 @@
+/*
+ * Copyright 2019 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 ATRACE_TAG ATRACE_TAG_GRAPHICS
+#include <utils/Trace.h>
+#include <vector>
+
+#include "TimeKeeper.h"
+#include "VSyncDispatch.h"
+#include "VSyncTracker.h"
+
+namespace android::scheduler {
+
+VSyncTracker::~VSyncTracker() = default;
+TimeKeeper::~TimeKeeper() = default;
+
+impl::VSyncDispatchEntry::VSyncDispatchEntry(std::string const& name,
+                                             std::function<void(nsecs_t)> const& cb)
+      : mName(name), mCallback(cb), mWorkDuration(0), mEarliestVsync(0) {}
+
+std::optional<nsecs_t> impl::VSyncDispatchEntry::lastExecutedVsyncTarget() const {
+    return mLastDispatchTime;
+}
+
+std::string_view impl::VSyncDispatchEntry::name() const {
+    return mName;
+}
+
+std::optional<nsecs_t> impl::VSyncDispatchEntry::wakeupTime() const {
+    if (!mArmedInfo) {
+        return {};
+    }
+    return {mArmedInfo->mActualWakeupTime};
+}
+
+nsecs_t impl::VSyncDispatchEntry::schedule(nsecs_t workDuration, nsecs_t earliestVsync,
+                                           VSyncTracker& tracker, nsecs_t now) {
+    mWorkDuration = workDuration;
+    mEarliestVsync = earliestVsync;
+    arm(tracker, now);
+    return mArmedInfo->mActualWakeupTime;
+}
+
+void impl::VSyncDispatchEntry::update(VSyncTracker& tracker, nsecs_t now) {
+    if (!mArmedInfo) {
+        return;
+    }
+    arm(tracker, now);
+}
+
+void impl::VSyncDispatchEntry::arm(VSyncTracker& tracker, nsecs_t now) {
+    auto const nextVsyncTime =
+            tracker.nextAnticipatedVSyncTimeFrom(std::max(mEarliestVsync, now + mWorkDuration));
+    mArmedInfo = {nextVsyncTime - mWorkDuration, nextVsyncTime};
+}
+
+void impl::VSyncDispatchEntry::disarm() {
+    mArmedInfo.reset();
+}
+
+nsecs_t impl::VSyncDispatchEntry::executing() {
+    mLastDispatchTime = mArmedInfo->mActualVsyncTime;
+    disarm();
+    return *mLastDispatchTime;
+}
+
+void impl::VSyncDispatchEntry::callback(nsecs_t t) {
+    {
+        std::lock_guard<std::mutex> lk(mRunningMutex);
+        mRunning = true;
+    }
+
+    mCallback(t);
+
+    std::lock_guard<std::mutex> lk(mRunningMutex);
+    mRunning = false;
+    mCv.notify_all();
+}
+
+void impl::VSyncDispatchEntry::ensureNotRunning() {
+    std::unique_lock<std::mutex> lk(mRunningMutex);
+    mCv.wait(lk, [this]() REQUIRES(mRunningMutex) { return !mRunning; });
+}
+
+VSyncDispatch::VSyncDispatch(std::unique_ptr<TimeKeeper> tk, VSyncTracker& tracker,
+                             nsecs_t timerSlack)
+      : mTimeKeeper(std::move(tk)), mTracker(tracker), mTimerSlack(timerSlack) {}
+
+VSyncDispatch::~VSyncDispatch() {
+    std::lock_guard<decltype(mMutex)> lk(mMutex);
+    cancelTimer();
+}
+
+void VSyncDispatch::cancelTimer() {
+    mIntendedWakeupTime = kInvalidTime;
+    mTimeKeeper->alarmCancel();
+}
+
+void VSyncDispatch::setTimer(nsecs_t targetTime, nsecs_t now) {
+    mIntendedWakeupTime = targetTime;
+    mTimeKeeper->alarmIn(std::bind(&VSyncDispatch::timerCallback, this), targetTime - now);
+}
+
+void VSyncDispatch::rearmTimer(nsecs_t now) {
+    rearmTimerSkippingUpdateFor(now, mCallbacks.end());
+}
+
+void VSyncDispatch::rearmTimerSkippingUpdateFor(nsecs_t now,
+                                                CallbackMap::iterator const& skipUpdateIt) {
+    std::optional<nsecs_t> min;
+    for (auto it = mCallbacks.begin(); it != mCallbacks.end(); it++) {
+        auto& callback = it->second;
+        if (!callback->wakeupTime()) {
+            continue;
+        }
+
+        if (it != skipUpdateIt) {
+            callback->update(mTracker, now);
+        }
+        auto const wakeupTime = *callback->wakeupTime();
+        if (!min || (min && *min > wakeupTime)) {
+            min = wakeupTime;
+        }
+    }
+
+    if (min && (min < mIntendedWakeupTime)) {
+        setTimer(*min, now);
+    } else {
+        cancelTimer();
+    }
+}
+
+void VSyncDispatch::timerCallback() {
+    struct Invocation {
+        std::shared_ptr<impl::VSyncDispatchEntry> callback;
+        nsecs_t timestamp;
+    };
+    std::vector<Invocation> invocations;
+    {
+        std::lock_guard<decltype(mMutex)> lk(mMutex);
+        for (auto it = mCallbacks.begin(); it != mCallbacks.end(); it++) {
+            auto& callback = it->second;
+            auto const wakeupTime = callback->wakeupTime();
+            if (!wakeupTime) {
+                continue;
+            }
+
+            if (*wakeupTime < mIntendedWakeupTime + mTimerSlack) {
+                callback->executing();
+                invocations.emplace_back(
+                        Invocation{callback, *callback->lastExecutedVsyncTarget()});
+            }
+        }
+
+        mIntendedWakeupTime = kInvalidTime;
+        rearmTimer(mTimeKeeper->now());
+    }
+
+    for (auto const& invocation : invocations) {
+        invocation.callback->callback(invocation.timestamp);
+    }
+}
+
+VSyncDispatch::CallbackToken VSyncDispatch::registerCallback(
+        std::function<void(nsecs_t)> const& callbackFn, std::string callbackName) {
+    std::lock_guard<decltype(mMutex)> lk(mMutex);
+    return CallbackToken{
+            mCallbacks
+                    .emplace(++mCallbackToken,
+                             std::make_shared<impl::VSyncDispatchEntry>(callbackName, callbackFn))
+                    .first->first};
+}
+
+void VSyncDispatch::unregisterCallback(CallbackToken token) {
+    std::shared_ptr<impl::VSyncDispatchEntry> entry = nullptr;
+    {
+        std::lock_guard<decltype(mMutex)> lk(mMutex);
+        auto it = mCallbacks.find(token);
+        if (it != mCallbacks.end()) {
+            entry = it->second;
+            mCallbacks.erase(it);
+        }
+    }
+
+    if (entry) {
+        entry->ensureNotRunning();
+    }
+}
+
+ScheduleResult VSyncDispatch::schedule(CallbackToken token, nsecs_t workDuration,
+                                       nsecs_t earliestVsync) {
+    auto result = ScheduleResult::Error;
+    {
+        std::lock_guard<decltype(mMutex)> lk(mMutex);
+
+        auto it = mCallbacks.find(token);
+        if (it == mCallbacks.end()) {
+            return result;
+        }
+        auto& callback = it->second;
+        result = callback->wakeupTime() ? ScheduleResult::ReScheduled : ScheduleResult::Scheduled;
+
+        auto const now = mTimeKeeper->now();
+        auto const wakeupTime = callback->schedule(workDuration, earliestVsync, mTracker, now);
+
+        if (wakeupTime < now - mTimerSlack || callback->lastExecutedVsyncTarget() > wakeupTime) {
+            return ScheduleResult::CannotSchedule;
+        }
+
+        if (wakeupTime < mIntendedWakeupTime - mTimerSlack) {
+            rearmTimerSkippingUpdateFor(now, it);
+        }
+    }
+
+    return result;
+}
+
+CancelResult VSyncDispatch::cancel(CallbackToken token) {
+    std::lock_guard<decltype(mMutex)> lk(mMutex);
+
+    auto it = mCallbacks.find(token);
+    if (it == mCallbacks.end()) {
+        return CancelResult::Error;
+    }
+    auto& callback = it->second;
+
+    if (callback->wakeupTime()) {
+        callback->disarm();
+        mIntendedWakeupTime = kInvalidTime;
+        rearmTimer(mTimeKeeper->now());
+        return CancelResult::Cancelled;
+    }
+    return CancelResult::TooLate;
+}
+
+VSyncCallbackRegistration::VSyncCallbackRegistration(VSyncDispatch& dispatch,
+                                                     std::function<void(nsecs_t)> const& callbackFn,
+                                                     std::string const& callbackName)
+      : mDispatch(dispatch),
+        mToken(dispatch.registerCallback(callbackFn, callbackName)),
+        mValidToken(true) {}
+
+VSyncCallbackRegistration::VSyncCallbackRegistration(VSyncCallbackRegistration&& other)
+      : mDispatch(other.mDispatch),
+        mToken(std::move(other.mToken)),
+        mValidToken(std::move(other.mValidToken)) {
+    other.mValidToken = false;
+}
+
+VSyncCallbackRegistration& VSyncCallbackRegistration::operator=(VSyncCallbackRegistration&& other) {
+    mDispatch = std::move(other.mDispatch);
+    mToken = std::move(other.mToken);
+    mValidToken = std::move(other.mValidToken);
+    other.mValidToken = false;
+    return *this;
+}
+
+VSyncCallbackRegistration::~VSyncCallbackRegistration() {
+    if (mValidToken) mDispatch.get().unregisterCallback(mToken);
+}
+
+ScheduleResult VSyncCallbackRegistration::schedule(nsecs_t workDuration, nsecs_t earliestVsync) {
+    if (!mValidToken) return ScheduleResult::Error;
+    return mDispatch.get().schedule(mToken, workDuration, earliestVsync);
+}
+
+CancelResult VSyncCallbackRegistration::cancel() {
+    if (!mValidToken) return CancelResult::Error;
+    return mDispatch.get().cancel(mToken);
+}
+
+} // namespace android::scheduler
diff --git a/services/surfaceflinger/Scheduler/VSyncDispatch.h b/services/surfaceflinger/Scheduler/VSyncDispatch.h
new file mode 100644
index 0000000..0050495
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/VSyncDispatch.h
@@ -0,0 +1,230 @@
+/*
+ * Copyright 2019 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.
+ */
+
+#pragma once
+
+#include <android-base/thread_annotations.h>
+#include <utils/Timers.h>
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+
+#include "StrongTyping.h"
+
+namespace android::scheduler {
+class TimeKeeper;
+class VSyncTracker;
+
+enum class ScheduleResult { Scheduled, ReScheduled, CannotSchedule, Error };
+enum class CancelResult { Cancelled, TooLate, Error };
+
+namespace impl {
+
+// VSyncDispatchEntry is a helper class representing internal state for each entry in VSyncDispatch
+// hoisted to public for unit testing.
+class VSyncDispatchEntry {
+public:
+    // This is the state of the entry. There are 3 states, armed, running, disarmed.
+    // Valid transition: disarmed -> armed ( when scheduled )
+    // Valid transition: armed -> running -> disarmed ( when timer is called)
+    // Valid transition: armed -> disarmed ( when cancelled )
+    VSyncDispatchEntry(std::string const& name, std::function<void(nsecs_t)> const& fn);
+    std::string_view name() const;
+
+    // Start: functions that are not threadsafe.
+    // Return the last vsync time this callback was invoked.
+    std::optional<nsecs_t> lastExecutedVsyncTarget() const;
+
+    // This moves the state from disarmed->armed and will calculate the wakeupTime.
+    nsecs_t schedule(nsecs_t workDuration, nsecs_t earliestVsync, VSyncTracker& tracker,
+                     nsecs_t now);
+    // This will update armed entries with the latest vsync information. Entry remains armed.
+    void update(VSyncTracker& tracker, nsecs_t now);
+
+    // This will return empty if not armed, or the next calculated wakeup time if armed.
+    // It will not update the wakeupTime.
+    std::optional<nsecs_t> wakeupTime() const;
+
+    // This moves state from armed->disarmed.
+    void disarm();
+
+    // This moves the state from armed->running.
+    // Store the timestamp that this was intended for as the last called timestamp.
+    nsecs_t executing();
+    // End: functions that are not threadsafe.
+
+    // Invoke the callback with the timestamp, moving the state from running->disarmed.
+    void callback(nsecs_t timestamp);
+    // Block calling thread while the callback is executing.
+    void ensureNotRunning();
+
+private:
+    void arm(VSyncTracker& tracker, nsecs_t now);
+    std::string const mName;
+    std::function<void(nsecs_t)> const mCallback;
+
+    nsecs_t mWorkDuration;
+    nsecs_t mEarliestVsync;
+
+    struct ArmingInfo {
+        nsecs_t mActualWakeupTime;
+        nsecs_t mActualVsyncTime;
+    };
+    std::optional<ArmingInfo> mArmedInfo;
+    std::optional<nsecs_t> mLastDispatchTime;
+
+    std::mutex mRunningMutex;
+    std::condition_variable mCv;
+    bool mRunning GUARDED_BY(mRunningMutex) = false;
+};
+
+} // namespace impl
+
+/*
+ * VSyncDispatch is a class that will dispatch callbacks relative to system vsync events.
+ */
+class VSyncDispatch {
+public:
+    using CallbackToken = StrongTyping<size_t, class CallbackTokenTag, Compare>;
+
+    /* creates a VsyncDispatch.
+     * \param [in]  a timekeeper object for dispatching events.
+     * \param [in]  a tracker object that is monitoring expected vsync events.
+     * \param [in]  a tunable in nanoseconds that indicates when events that fall close together
+     *              should be dispatched in one timer wakeup.
+     */
+    explicit VSyncDispatch(std::unique_ptr<TimeKeeper> tk, VSyncTracker& tracker,
+                           nsecs_t timerSlack);
+    ~VSyncDispatch();
+
+    /*
+     * Registers a callback that will be called at designated points on the vsync timeline.
+     * The callback can be scheduled, rescheduled targeting vsync times, or cancelled.
+     * The token returned must be cleaned up via unregisterCallback.
+     *
+     * \param [in] callbackFn   A function to schedule for callback. The resources needed to invoke
+     *                          callbackFn must have lifetimes encompassing the lifetime of the
+     *                          CallbackToken returned.
+     * \param [in] callbackName A human-readable, unique name to identify the callback.
+     * \return                  A token that can be used to schedule, reschedule, or cancel the
+     *                          invocation of callbackFn.
+     *
+     */
+    CallbackToken registerCallback(std::function<void(nsecs_t)> const& callbackFn,
+                                   std::string callbackName);
+
+    /*
+     * Unregisters a callback.
+     *
+     * \param [in] token        The callback to unregister.
+     *
+     */
+    void unregisterCallback(CallbackToken token);
+
+    /*
+     * Schedules the registered callback to be dispatched.
+     *
+     * The callback will be dispatched at 'workDuration' nanoseconds before a vsync event.
+     *
+     * The caller designates the earliest vsync event that should be targeted by the earliestVsync
+     * parameter.
+     * The callback will be scheduled at (workDuration - predictedVsync), where predictedVsync
+     * is the first vsync event time where ( predictedVsync >= earliestVsync ).
+     *
+     * If (workDuration - earliestVsync) is in the past, or if a callback has already been
+     * dispatched for the predictedVsync, an error will be returned.
+     *
+     * It is valid to reschedule a callback to a different time.
+     *
+     * \param [in] token           The callback to schedule.
+     * \param [in] workDuration    The time before the actual vsync time to invoke the callback
+     *                             associated with token.
+     * \param [in] earliestVsync   The targeted display time. This will be snapped to the closest
+     *                             predicted vsync time after earliestVsync.
+     * \return                     A ScheduleResult::Scheduled if callback was scheduled.
+     *                             A ScheduleResult::ReScheduled if callback was rescheduled.
+     *                             A ScheduleResult::CannotSchedule
+     *                             if (workDuration - earliestVsync) is in the past, or
+     *                             if a callback was dispatched for the predictedVsync already.
+     *                             A ScheduleResult::Error if there was another error.
+     */
+    ScheduleResult schedule(CallbackToken token, nsecs_t workDuration, nsecs_t earliestVsync);
+
+    /* Cancels a scheduled callback, if possible.
+     *
+     * \param [in] token    The callback to cancel.
+     * \return              A CancelResult::TooLate if the callback was already dispatched.
+     *                      A CancelResult::Cancelled if the callback was successfully cancelled.
+     *                      A CancelResult::Error if there was an pre-condition violation.
+     */
+    CancelResult cancel(CallbackToken token);
+
+private:
+    VSyncDispatch(VSyncDispatch const&) = delete;
+    VSyncDispatch& operator=(VSyncDispatch const&) = delete;
+
+    using CallbackMap = std::unordered_map<size_t, std::shared_ptr<impl::VSyncDispatchEntry>>;
+
+    void timerCallback();
+    void setTimer(nsecs_t, nsecs_t) REQUIRES(mMutex);
+    void rearmTimer(nsecs_t now) REQUIRES(mMutex);
+    void rearmTimerSkippingUpdateFor(nsecs_t now, CallbackMap::iterator const& skipUpdate)
+            REQUIRES(mMutex);
+    void cancelTimer() REQUIRES(mMutex);
+
+    static constexpr nsecs_t kInvalidTime = std::numeric_limits<int64_t>::max();
+    std::unique_ptr<TimeKeeper> const mTimeKeeper;
+    VSyncTracker& mTracker;
+    nsecs_t const mTimerSlack;
+
+    std::mutex mutable mMutex;
+    size_t mCallbackToken GUARDED_BY(mMutex) = 0;
+
+    CallbackMap mCallbacks GUARDED_BY(mMutex);
+    nsecs_t mIntendedWakeupTime GUARDED_BY(mMutex) = kInvalidTime;
+};
+
+/*
+ * Helper class to operate on registered callbacks. It is up to user of the class to ensure
+ * that VsyncDispatch lifetime exceeds the lifetime of VSyncCallbackRegistation.
+ */
+class VSyncCallbackRegistration {
+public:
+    VSyncCallbackRegistration(VSyncDispatch&, std::function<void(nsecs_t)> const& callbackFn,
+                              std::string const& callbackName);
+    VSyncCallbackRegistration(VSyncCallbackRegistration&&);
+    VSyncCallbackRegistration& operator=(VSyncCallbackRegistration&&);
+    ~VSyncCallbackRegistration();
+
+    // See documentation for VSyncDispatch::schedule.
+    ScheduleResult schedule(nsecs_t workDuration, nsecs_t earliestVsync);
+
+    // See documentation for VSyncDispatch::cancel.
+    CancelResult cancel();
+
+private:
+    VSyncCallbackRegistration(VSyncCallbackRegistration const&) = delete;
+    VSyncCallbackRegistration& operator=(VSyncCallbackRegistration const&) = delete;
+
+    std::reference_wrapper<VSyncDispatch> mDispatch;
+    VSyncDispatch::CallbackToken mToken;
+    bool mValidToken;
+};
+
+} // namespace android::scheduler
diff --git a/services/surfaceflinger/Scheduler/VSyncTracker.h b/services/surfaceflinger/Scheduler/VSyncTracker.h
new file mode 100644
index 0000000..97b9620
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/VSyncTracker.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2019 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.
+ */
+
+#pragma once
+
+#include <utils/Timers.h>
+#include "VSyncDispatch.h"
+
+namespace android::scheduler {
+/*
+ * VSyncTracker is an interface for providing estimates on future Vsync signal times based on
+ * historical vsync timing data.
+ */
+class VSyncTracker {
+public:
+    virtual ~VSyncTracker();
+
+    /*
+     * Adds a known timestamp from a vsync timing source (HWVsync signal, present fence)
+     * to the model.
+     *
+     * \param [in] timestamp    The timestamp when the vsync signal was.
+     */
+    virtual void addVsyncTimestamp(nsecs_t timestamp) = 0;
+
+    /*
+     * Access the next anticipated vsync time such that the anticipated time >= timePoint.
+     * This will always give the best accurate at the time of calling; multiple
+     * calls with the same timePoint might give differing values if the internal model
+     * is updated.
+     *
+     * \param [in] timePoint    The point in time after which to estimate a vsync event.
+     * \return                  A prediction of the timestamp of a vsync event.
+     */
+    virtual nsecs_t nextAnticipatedVSyncTimeFrom(nsecs_t timePoint) const = 0;
+
+protected:
+    VSyncTracker(VSyncTracker const&) = delete;
+    VSyncTracker& operator=(VSyncTracker const&) = delete;
+    VSyncTracker() = default;
+};
+
+} // namespace android::scheduler
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index f85da20..246a62f 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -54,6 +54,7 @@
         "FrameTracerTest.cpp",
         "TransactionApplicationTest.cpp",
         "StrongTypingTest.cpp",
+        "VSyncDispatchTest.cpp",
         "mock/DisplayHardware/MockComposer.cpp",
         "mock/DisplayHardware/MockDisplay.cpp",
         "mock/DisplayHardware/MockPowerAdvisor.cpp",
diff --git a/services/surfaceflinger/tests/unittests/VSyncDispatchTest.cpp b/services/surfaceflinger/tests/unittests/VSyncDispatchTest.cpp
new file mode 100644
index 0000000..d1ed7e3
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/VSyncDispatchTest.cpp
@@ -0,0 +1,680 @@
+/*
+ * Copyright 2019 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.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "LibSurfaceFlingerUnittests"
+#define LOG_NDEBUG 0
+
+#include "Scheduler/TimeKeeper.h"
+#include "Scheduler/VSyncDispatch.h"
+#include "Scheduler/VSyncTracker.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <thread>
+
+using namespace testing;
+using namespace std::literals;
+namespace android::scheduler {
+
+class MockVSyncTracker : public VSyncTracker {
+public:
+    MockVSyncTracker(nsecs_t period) : mPeriod{period} {
+        ON_CALL(*this, nextAnticipatedVSyncTimeFrom(_))
+                .WillByDefault(Invoke(this, &MockVSyncTracker::nextVSyncTime));
+    }
+
+    MOCK_METHOD1(addVsyncTimestamp, void(nsecs_t));
+    MOCK_CONST_METHOD1(nextAnticipatedVSyncTimeFrom, nsecs_t(nsecs_t));
+
+    nsecs_t nextVSyncTime(nsecs_t timePoint) const {
+        if (timePoint % mPeriod == 0) {
+            return timePoint;
+        }
+        return (timePoint - (timePoint % mPeriod) + mPeriod);
+    }
+
+protected:
+    nsecs_t const mPeriod;
+};
+
+class ControllableClock : public TimeKeeper {
+public:
+    ControllableClock() {
+        ON_CALL(*this, alarmIn(_, _))
+                .WillByDefault(Invoke(this, &ControllableClock::alarmInDefaultBehavior));
+        ON_CALL(*this, now()).WillByDefault(Invoke(this, &ControllableClock::fakeTime));
+    }
+
+    MOCK_CONST_METHOD0(now, nsecs_t());
+    MOCK_METHOD2(alarmIn, void(std::function<void()> const&, nsecs_t time));
+    MOCK_METHOD0(alarmCancel, void());
+
+    void alarmInDefaultBehavior(std::function<void()> const& callback, nsecs_t time) {
+        mCallback = callback;
+        mNextCallbackTime = time + mCurrentTime;
+    }
+
+    nsecs_t fakeTime() const { return mCurrentTime; }
+
+    void advanceToNextCallback() {
+        mCurrentTime = mNextCallbackTime;
+        if (mCallback) {
+            mCallback();
+        }
+    }
+
+    void advanceBy(nsecs_t advancement) {
+        mCurrentTime += advancement;
+        if (mCurrentTime >= mNextCallbackTime && mCallback) {
+            mCallback();
+        }
+    };
+
+private:
+    std::function<void()> mCallback;
+    nsecs_t mNextCallbackTime = 0;
+    nsecs_t mCurrentTime = 0;
+};
+
+class CountingCallback {
+public:
+    CountingCallback(VSyncDispatch& dispatch)
+          : mDispatch(dispatch),
+            mToken(dispatch.registerCallback(std::bind(&CountingCallback::counter, this,
+                                                       std::placeholders::_1),
+                                             "test")) {}
+    ~CountingCallback() { mDispatch.unregisterCallback(mToken); }
+
+    operator VSyncDispatch::CallbackToken() const { return mToken; }
+
+    void counter(nsecs_t time) { mCalls.push_back(time); }
+
+    VSyncDispatch& mDispatch;
+    VSyncDispatch::CallbackToken mToken;
+    std::vector<nsecs_t> mCalls;
+};
+
+class PausingCallback {
+public:
+    PausingCallback(VSyncDispatch& dispatch, std::chrono::milliseconds pauseAmount)
+          : mDispatch(dispatch),
+            mToken(dispatch.registerCallback(std::bind(&PausingCallback::pause, this,
+                                                       std::placeholders::_1),
+                                             "test")),
+            mRegistered(true),
+            mPauseAmount(pauseAmount) {}
+    ~PausingCallback() { unregister(); }
+
+    operator VSyncDispatch::CallbackToken() const { return mToken; }
+
+    void pause(nsecs_t) {
+        std::unique_lock<std::mutex> lk(mMutex);
+        mPause = true;
+        mCv.notify_all();
+
+        mCv.wait_for(lk, mPauseAmount, [this] { return !mPause; });
+
+        mResourcePresent = (mResource.lock() != nullptr);
+    }
+
+    bool waitForPause() {
+        std::unique_lock<std::mutex> lk(mMutex);
+        auto waiting = mCv.wait_for(lk, 10s, [this] { return mPause; });
+        return waiting;
+    }
+
+    void stashResource(std::weak_ptr<void> const& resource) { mResource = resource; }
+
+    bool resourcePresent() { return mResourcePresent; }
+
+    void unpause() {
+        std::unique_lock<std::mutex> lk(mMutex);
+        mPause = false;
+        mCv.notify_all();
+    }
+
+    void unregister() {
+        if (mRegistered) {
+            mDispatch.unregisterCallback(mToken);
+            mRegistered = false;
+        }
+    }
+
+    VSyncDispatch& mDispatch;
+    VSyncDispatch::CallbackToken mToken;
+    bool mRegistered = true;
+
+    std::mutex mMutex;
+    std::condition_variable mCv;
+    bool mPause = false;
+    std::weak_ptr<void> mResource;
+    bool mResourcePresent = false;
+    std::chrono::milliseconds const mPauseAmount;
+};
+
+class VSyncDispatchTest : public testing::Test {
+protected:
+    std::unique_ptr<TimeKeeper> createTimeKeeper() {
+        class TimeKeeperWrapper : public TimeKeeper {
+        public:
+            TimeKeeperWrapper(TimeKeeper& control) : mControllableClock(control) {}
+            void alarmIn(std::function<void()> const& callback, nsecs_t time) final {
+                mControllableClock.alarmIn(callback, time);
+            }
+            void alarmCancel() final { mControllableClock.alarmCancel(); }
+            nsecs_t now() const final { return mControllableClock.now(); }
+
+        private:
+            TimeKeeper& mControllableClock;
+        };
+        return std::make_unique<TimeKeeperWrapper>(mMockClock);
+    }
+
+    ~VSyncDispatchTest() {
+        // destructor of  dispatch will cancelAlarm(). Ignore final cancel in common test.
+        Mock::VerifyAndClearExpectations(&mMockClock);
+    }
+
+    void advanceToNextCallback() { mMockClock.advanceToNextCallback(); }
+
+    NiceMock<ControllableClock> mMockClock;
+    static nsecs_t constexpr mDispatchGroupThreshold = 5;
+    nsecs_t const mPeriod = 1000;
+    NiceMock<MockVSyncTracker> mStubTracker{mPeriod};
+    VSyncDispatch mDispatch{createTimeKeeper(), mStubTracker, mDispatchGroupThreshold};
+};
+
+TEST_F(VSyncDispatchTest, unregistersSetAlarmOnDestruction) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 900));
+    EXPECT_CALL(mMockClock, alarmCancel());
+    {
+        VSyncDispatch mDispatch{createTimeKeeper(), mStubTracker, mDispatchGroupThreshold};
+        CountingCallback cb(mDispatch);
+        EXPECT_EQ(mDispatch.schedule(cb, 100, 1000), ScheduleResult::Scheduled);
+    }
+}
+
+TEST_F(VSyncDispatchTest, basicAlarmSettingFuture) {
+    auto intended = mPeriod - 230;
+    EXPECT_CALL(mMockClock, alarmIn(_, 900));
+
+    CountingCallback cb(mDispatch);
+    EXPECT_EQ(mDispatch.schedule(cb, 100, intended), ScheduleResult::Scheduled);
+    advanceToNextCallback();
+
+    ASSERT_THAT(cb.mCalls.size(), Eq(1));
+    EXPECT_THAT(cb.mCalls[0], Eq(mPeriod));
+}
+
+TEST_F(VSyncDispatchTest, basicAlarmSettingFutureWithAdjustmentToTrueVsync) {
+    EXPECT_CALL(mStubTracker, nextAnticipatedVSyncTimeFrom(1000)).WillOnce(Return(1150));
+    EXPECT_CALL(mMockClock, alarmIn(_, 1050));
+
+    CountingCallback cb(mDispatch);
+    mDispatch.schedule(cb, 100, mPeriod);
+    advanceToNextCallback();
+
+    ASSERT_THAT(cb.mCalls.size(), Eq(1));
+    EXPECT_THAT(cb.mCalls[0], Eq(1150));
+}
+
+TEST_F(VSyncDispatchTest, basicAlarmSettingAdjustmentPast) {
+    auto const now = 234;
+    mMockClock.advanceBy(234);
+    auto const workDuration = 10 * mPeriod;
+    EXPECT_CALL(mStubTracker, nextAnticipatedVSyncTimeFrom(now + workDuration))
+            .WillOnce(Return(mPeriod * 11));
+    EXPECT_CALL(mMockClock, alarmIn(_, mPeriod - now));
+
+    CountingCallback cb(mDispatch);
+    EXPECT_EQ(mDispatch.schedule(cb, workDuration, mPeriod), ScheduleResult::Scheduled);
+}
+
+TEST_F(VSyncDispatchTest, basicAlarmCancel) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 900));
+    EXPECT_CALL(mMockClock, alarmCancel());
+
+    CountingCallback cb(mDispatch);
+    EXPECT_EQ(mDispatch.schedule(cb, 100, mPeriod), ScheduleResult::Scheduled);
+    EXPECT_EQ(mDispatch.cancel(cb), CancelResult::Cancelled);
+}
+
+TEST_F(VSyncDispatchTest, basicAlarmCancelTooLate) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 900));
+    EXPECT_CALL(mMockClock, alarmCancel());
+
+    CountingCallback cb(mDispatch);
+    EXPECT_EQ(mDispatch.schedule(cb, 100, mPeriod), ScheduleResult::Scheduled);
+    mMockClock.advanceBy(950);
+    EXPECT_EQ(mDispatch.cancel(cb), CancelResult::TooLate);
+}
+
+TEST_F(VSyncDispatchTest, basicAlarmCancelTooLateWhenRunning) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 900));
+    EXPECT_CALL(mMockClock, alarmCancel());
+
+    PausingCallback cb(mDispatch, std::chrono::duration_cast<std::chrono::milliseconds>(1s));
+    EXPECT_EQ(mDispatch.schedule(cb, 100, mPeriod), ScheduleResult::Scheduled);
+
+    std::thread pausingThread([&] { mMockClock.advanceToNextCallback(); });
+    EXPECT_TRUE(cb.waitForPause());
+    EXPECT_EQ(mDispatch.cancel(cb), CancelResult::TooLate);
+    cb.unpause();
+    pausingThread.join();
+}
+
+TEST_F(VSyncDispatchTest, unregisterSynchronizes) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 900));
+    EXPECT_CALL(mMockClock, alarmCancel());
+
+    auto resource = std::make_shared<int>(110);
+
+    PausingCallback cb(mDispatch, 50ms);
+    cb.stashResource(resource);
+    EXPECT_EQ(mDispatch.schedule(cb, 100, mPeriod), ScheduleResult::Scheduled);
+
+    std::thread pausingThread([&] { mMockClock.advanceToNextCallback(); });
+    EXPECT_TRUE(cb.waitForPause());
+
+    cb.unregister();
+    resource.reset();
+
+    cb.unpause();
+    pausingThread.join();
+
+    EXPECT_TRUE(cb.resourcePresent());
+}
+
+TEST_F(VSyncDispatchTest, basicTwoAlarmSetting) {
+    EXPECT_CALL(mStubTracker, nextAnticipatedVSyncTimeFrom(1000))
+            .Times(4)
+            .WillOnce(Return(1055))
+            .WillOnce(Return(1063))
+            .WillOnce(Return(1063))
+            .WillOnce(Return(1075));
+
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 955)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 813)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 162)).InSequence(seq);
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+
+    mDispatch.schedule(cb0, 100, mPeriod);
+    mDispatch.schedule(cb1, 250, mPeriod);
+
+    advanceToNextCallback();
+    advanceToNextCallback();
+
+    ASSERT_THAT(cb0.mCalls.size(), Eq(1));
+    EXPECT_THAT(cb0.mCalls[0], Eq(1075));
+    ASSERT_THAT(cb1.mCalls.size(), Eq(1));
+    EXPECT_THAT(cb1.mCalls[0], Eq(1063));
+}
+
+TEST_F(VSyncDispatchTest, rearmsFaroutTimeoutWhenCancellingCloseOne) {
+    EXPECT_CALL(mStubTracker, nextAnticipatedVSyncTimeFrom(_))
+            .Times(4)
+            .WillOnce(Return(10000))
+            .WillOnce(Return(1000))
+            .WillOnce(Return(10000))
+            .WillOnce(Return(10000));
+
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 9900)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 750)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 9900)).InSequence(seq);
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+
+    mDispatch.schedule(cb0, 100, mPeriod * 10);
+    mDispatch.schedule(cb1, 250, mPeriod);
+    mDispatch.cancel(cb1);
+}
+
+TEST_F(VSyncDispatchTest, noUnnecessaryRearmsWhenRescheduling) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 600)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 100)).InSequence(seq);
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+
+    mDispatch.schedule(cb0, 400, 1000);
+    mDispatch.schedule(cb1, 200, 1000);
+    mDispatch.schedule(cb1, 300, 1000);
+    advanceToNextCallback();
+}
+
+TEST_F(VSyncDispatchTest, necessaryRearmsWhenModifying) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 600)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 500)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 100)).InSequence(seq);
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+
+    mDispatch.schedule(cb0, 400, 1000);
+    mDispatch.schedule(cb1, 200, 1000);
+    mDispatch.schedule(cb1, 500, 1000);
+    advanceToNextCallback();
+}
+
+TEST_F(VSyncDispatchTest, modifyIntoGroup) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 600)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 1000)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 990)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 10)).InSequence(seq);
+
+    auto offset = 400;
+    auto closeOffset = offset + mDispatchGroupThreshold - 1;
+    auto notCloseOffset = offset + 2 * mDispatchGroupThreshold;
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+
+    mDispatch.schedule(cb0, 400, 1000);
+    mDispatch.schedule(cb1, 200, 1000);
+    mDispatch.schedule(cb1, closeOffset, 1000);
+
+    advanceToNextCallback();
+    ASSERT_THAT(cb0.mCalls.size(), Eq(1));
+    EXPECT_THAT(cb0.mCalls[0], Eq(mPeriod));
+    ASSERT_THAT(cb1.mCalls.size(), Eq(1));
+    EXPECT_THAT(cb1.mCalls[0], Eq(mPeriod));
+
+    mDispatch.schedule(cb0, 400, 2000);
+    mDispatch.schedule(cb1, notCloseOffset, 2000);
+    advanceToNextCallback();
+    ASSERT_THAT(cb1.mCalls.size(), Eq(2));
+    EXPECT_THAT(cb1.mCalls[1], Eq(2000));
+
+    advanceToNextCallback();
+    ASSERT_THAT(cb0.mCalls.size(), Eq(2));
+    EXPECT_THAT(cb0.mCalls[1], Eq(2000));
+}
+
+TEST_F(VSyncDispatchTest, rearmsWhenEndingAndDoesntCancel) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 900));
+    EXPECT_CALL(mMockClock, alarmIn(_, 800));
+    EXPECT_CALL(mMockClock, alarmIn(_, 100));
+    EXPECT_CALL(mMockClock, alarmCancel());
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+
+    mDispatch.schedule(cb0, 100, 1000);
+    mDispatch.schedule(cb1, 200, 1000);
+    advanceToNextCallback();
+    EXPECT_EQ(mDispatch.cancel(cb0), CancelResult::Cancelled);
+}
+
+TEST_F(VSyncDispatchTest, setAlarmCallsAtCorrectTimeWithChangingVsync) {
+    EXPECT_CALL(mStubTracker, nextAnticipatedVSyncTimeFrom(_))
+            .Times(3)
+            .WillOnce(Return(950))
+            .WillOnce(Return(1975))
+            .WillOnce(Return(2950));
+
+    CountingCallback cb(mDispatch);
+    mDispatch.schedule(cb, 100, 920);
+
+    mMockClock.advanceBy(850);
+    EXPECT_THAT(cb.mCalls.size(), Eq(1));
+
+    mDispatch.schedule(cb, 100, 1900);
+    mMockClock.advanceBy(900);
+    EXPECT_THAT(cb.mCalls.size(), Eq(1));
+    mMockClock.advanceBy(125);
+    EXPECT_THAT(cb.mCalls.size(), Eq(2));
+
+    mDispatch.schedule(cb, 100, 2900);
+    mMockClock.advanceBy(975);
+    EXPECT_THAT(cb.mCalls.size(), Eq(3));
+}
+
+TEST_F(VSyncDispatchTest, callbackReentrancy) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 900)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 1000)).InSequence(seq);
+
+    VSyncDispatch::CallbackToken tmp;
+    tmp = mDispatch.registerCallback([&](auto) { mDispatch.schedule(tmp, 100, 2000); }, "o.o");
+
+    mDispatch.schedule(tmp, 100, 1000);
+    advanceToNextCallback();
+}
+
+TEST_F(VSyncDispatchTest, callbackReentrantWithPastWakeup) {
+    VSyncDispatch::CallbackToken tmp;
+    tmp = mDispatch.registerCallback(
+            [&](auto) {
+                EXPECT_EQ(mDispatch.schedule(tmp, 400, 1000), ScheduleResult::CannotSchedule);
+            },
+            "oo");
+
+    mDispatch.schedule(tmp, 999, 1000);
+    advanceToNextCallback();
+}
+
+TEST_F(VSyncDispatchTest, modificationsAroundVsyncTime) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 1000)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 200)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 1000)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 150)).InSequence(seq);
+
+    CountingCallback cb(mDispatch);
+    mDispatch.schedule(cb, 0, 1000);
+
+    mMockClock.advanceBy(750);
+    mDispatch.schedule(cb, 50, 1000);
+
+    advanceToNextCallback();
+    mDispatch.schedule(cb, 50, 2000);
+
+    mMockClock.advanceBy(800);
+    mDispatch.schedule(cb, 100, 2000);
+}
+
+TEST_F(VSyncDispatchTest, lateModifications) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 500)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 400)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 350)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 950)).InSequence(seq);
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+
+    mDispatch.schedule(cb0, 500, 1000);
+    mDispatch.schedule(cb1, 100, 1000);
+
+    advanceToNextCallback();
+    mDispatch.schedule(cb0, 200, 2000);
+    mDispatch.schedule(cb1, 150, 1000);
+
+    advanceToNextCallback();
+    advanceToNextCallback();
+}
+
+TEST_F(VSyncDispatchTest, doesntCancelPriorValidTimerForFutureMod) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 500)).InSequence(seq);
+
+    CountingCallback cb0(mDispatch);
+    CountingCallback cb1(mDispatch);
+    mDispatch.schedule(cb0, 500, 1000);
+    mDispatch.schedule(cb1, 500, 20000);
+}
+
+TEST_F(VSyncDispatchTest, setsTimerAfterCancellation) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmIn(_, 500)).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmCancel()).InSequence(seq);
+    EXPECT_CALL(mMockClock, alarmIn(_, 900)).InSequence(seq);
+
+    CountingCallback cb0(mDispatch);
+    mDispatch.schedule(cb0, 500, 1000);
+    mDispatch.cancel(cb0);
+    mDispatch.schedule(cb0, 100, 1000);
+}
+
+TEST_F(VSyncDispatchTest, makingUpIdsError) {
+    VSyncDispatch::CallbackToken token(100);
+    EXPECT_THAT(mDispatch.schedule(token, 100, 1000), Eq(ScheduleResult::Error));
+    EXPECT_THAT(mDispatch.cancel(token), Eq(CancelResult::Error));
+}
+
+TEST_F(VSyncDispatchTest, distinguishesScheduleAndReschedule) {
+    CountingCallback cb0(mDispatch);
+    EXPECT_EQ(mDispatch.schedule(cb0, 500, 1000), ScheduleResult::Scheduled);
+    EXPECT_EQ(mDispatch.schedule(cb0, 100, 1000), ScheduleResult::ReScheduled);
+}
+
+TEST_F(VSyncDispatchTest, helperMove) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 500)).Times(1);
+    EXPECT_CALL(mMockClock, alarmCancel()).Times(1);
+
+    VSyncCallbackRegistration cb(
+            mDispatch, [](auto) {}, "");
+    VSyncCallbackRegistration cb1(std::move(cb));
+    cb.schedule(100, 1000);
+    cb.cancel();
+
+    cb1.schedule(500, 1000);
+    cb1.cancel();
+}
+
+TEST_F(VSyncDispatchTest, helperMoveAssign) {
+    EXPECT_CALL(mMockClock, alarmIn(_, 500)).Times(1);
+    EXPECT_CALL(mMockClock, alarmCancel()).Times(1);
+
+    VSyncCallbackRegistration cb(
+            mDispatch, [](auto) {}, "");
+    VSyncCallbackRegistration cb1(
+            mDispatch, [](auto) {}, "");
+    cb1 = std::move(cb);
+    cb.schedule(100, 1000);
+    cb.cancel();
+
+    cb1.schedule(500, 1000);
+    cb1.cancel();
+}
+
+class VSyncDispatchEntryTest : public testing::Test {
+protected:
+    nsecs_t const mPeriod = 1000;
+    NiceMock<MockVSyncTracker> mStubTracker{mPeriod};
+};
+
+TEST_F(VSyncDispatchEntryTest, stateAfterInitialization) {
+    std::string name("basicname");
+    impl::VSyncDispatchEntry entry(name, [](auto) {});
+    EXPECT_THAT(entry.name(), Eq(name));
+    EXPECT_FALSE(entry.lastExecutedVsyncTarget());
+    EXPECT_FALSE(entry.wakeupTime());
+}
+
+TEST_F(VSyncDispatchEntryTest, stateScheduling) {
+    impl::VSyncDispatchEntry entry("test", [](auto) {});
+
+    EXPECT_FALSE(entry.wakeupTime());
+    auto const wakeup = entry.schedule(100, 500, mStubTracker, 0);
+    auto const queried = entry.wakeupTime();
+    ASSERT_TRUE(queried);
+    EXPECT_THAT(*queried, Eq(wakeup));
+    EXPECT_THAT(*queried, Eq(900));
+
+    entry.disarm();
+    EXPECT_FALSE(entry.wakeupTime());
+}
+
+TEST_F(VSyncDispatchEntryTest, stateSchedulingReallyLongWakeupLatency) {
+    auto const duration = 500;
+    auto const now = 8750;
+
+    EXPECT_CALL(mStubTracker, nextAnticipatedVSyncTimeFrom(now + duration))
+            .Times(1)
+            .WillOnce(Return(10000));
+    impl::VSyncDispatchEntry entry("test", [](auto) {});
+
+    EXPECT_FALSE(entry.wakeupTime());
+    auto const wakeup = entry.schedule(500, 994, mStubTracker, now);
+    auto const queried = entry.wakeupTime();
+    ASSERT_TRUE(queried);
+    EXPECT_THAT(*queried, Eq(wakeup));
+    EXPECT_THAT(*queried, Eq(9500));
+}
+
+TEST_F(VSyncDispatchEntryTest, runCallback) {
+    auto callCount = 0;
+    auto calledTime = 0;
+    impl::VSyncDispatchEntry entry("test", [&](auto time) {
+        callCount++;
+        calledTime = time;
+    });
+
+    auto const wakeup = entry.schedule(100, 500, mStubTracker, 0);
+    EXPECT_THAT(wakeup, Eq(900));
+
+    entry.callback(entry.executing());
+
+    EXPECT_THAT(callCount, Eq(1));
+    EXPECT_THAT(calledTime, Eq(mPeriod));
+    EXPECT_FALSE(entry.wakeupTime());
+    auto lastCalledTarget = entry.lastExecutedVsyncTarget();
+    ASSERT_TRUE(lastCalledTarget);
+    EXPECT_THAT(*lastCalledTarget, Eq(mPeriod));
+}
+
+TEST_F(VSyncDispatchEntryTest, updateCallback) {
+    EXPECT_CALL(mStubTracker, nextAnticipatedVSyncTimeFrom(_))
+            .Times(2)
+            .WillOnce(Return(1000))
+            .WillOnce(Return(1020));
+
+    impl::VSyncDispatchEntry entry("test", [](auto) {});
+
+    EXPECT_FALSE(entry.wakeupTime());
+    entry.update(mStubTracker, 0);
+    EXPECT_FALSE(entry.wakeupTime());
+
+    auto const wakeup = entry.schedule(100, 500, mStubTracker, 0);
+    EXPECT_THAT(wakeup, Eq(900));
+
+    entry.update(mStubTracker, 0);
+    auto const queried = entry.wakeupTime();
+    ASSERT_TRUE(queried);
+    EXPECT_THAT(*queried, Eq(920));
+}
+
+TEST_F(VSyncDispatchEntryTest, skipsUpdateIfJustScheduled) {
+    impl::VSyncDispatchEntry entry("test", [](auto) {});
+    auto const wakeup = entry.schedule(100, 500, mStubTracker, 0);
+    entry.update(mStubTracker, 0);
+
+    auto const queried = entry.wakeupTime();
+    ASSERT_TRUE(queried);
+    EXPECT_THAT(*queried, Eq(wakeup));
+}
+
+} // namespace android::scheduler