Fix wallpaper window multi-touch

If the touched window has a wallpaper, then the touch event will be
duplicated to the wallpaper window when the foreground window received
a touch event.

When the foreground supports split touch, the wallpaper should deliver
the same events of foreground window.

And when the foreground window is transferred (caused by slippery or
transfer touch) to the new touched window, it has to check if the
wallpaper window should deliver the cancel event or keep in current
touch state.

Bug: 240308355
Test: atest inputflinger_tests
Change-Id: Ie53279f18838c459e528b24709aebf739290dc41
(cherry picked from commit c539dbb9812e30632ca2946ef6b1150127db0182)
Merged-In: Ie53279f18838c459e528b24709aebf739290dc41
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index 3267753..3b1a830 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -2196,8 +2196,31 @@
             // Update the temporary touch state.
             BitSet32 pointerIds;
             pointerIds.markBit(entry.pointerProperties[pointerIndex].id);
-
             tempTouchState.addOrUpdateWindow(windowHandle, targetFlags, pointerIds);
+
+            // If this is the pointer going down and the touched window has a wallpaper
+            // then also add the touched wallpaper windows so they are locked in for the duration
+            // of the touch gesture.
+            // We do not collect wallpapers during HOVER_MOVE or SCROLL because the wallpaper
+            // engine only supports touch events.  We would need to add a mechanism similar
+            // to View.onGenericMotionEvent to enable wallpapers to handle these events.
+            if (maskedAction == AMOTION_EVENT_ACTION_DOWN ||
+                maskedAction == AMOTION_EVENT_ACTION_POINTER_DOWN) {
+                if ((targetFlags & InputTarget::FLAG_FOREGROUND) &&
+                    windowHandle->getInfo()->inputConfig.test(
+                            gui::WindowInfo::InputConfig::DUPLICATE_TOUCH_TO_WALLPAPER)) {
+                    sp<WindowInfoHandle> wallpaper = findWallpaperWindowBelow(windowHandle);
+                    if (wallpaper != nullptr) {
+                        int32_t wallpaperFlags = InputTarget::FLAG_WINDOW_IS_OBSCURED |
+                                InputTarget::FLAG_WINDOW_IS_PARTIALLY_OBSCURED |
+                                InputTarget::FLAG_DISPATCH_AS_IS;
+                        if (isSplit) {
+                            wallpaperFlags |= InputTarget::FLAG_SPLIT;
+                        }
+                        tempTouchState.addOrUpdateWindow(wallpaper, wallpaperFlags, pointerIds);
+                    }
+                }
+            }
         }
     } else {
         /* Case 2: Pointer move, up, cancel or non-splittable pointer down. */
@@ -2274,6 +2297,10 @@
                 BitSet32 pointerIds;
                 pointerIds.markBit(entry.pointerProperties[0].id);
                 tempTouchState.addOrUpdateWindow(newTouchedWindowHandle, targetFlags, pointerIds);
+
+                // Check if the wallpaper window should deliver the corresponding event.
+                slipWallpaperTouch(targetFlags, oldTouchedWindowHandle, newTouchedWindowHandle,
+                                   tempTouchState, pointerIds);
             }
         }
 
@@ -2379,39 +2406,6 @@
         }
     }
 
-    // If this is the first pointer going down and the touched window has a wallpaper
-    // then also add the touched wallpaper windows so they are locked in for the duration
-    // of the touch gesture.
-    // We do not collect wallpapers during HOVER_MOVE or SCROLL because the wallpaper
-    // engine only supports touch events.  We would need to add a mechanism similar
-    // to View.onGenericMotionEvent to enable wallpapers to handle these events.
-    if (maskedAction == AMOTION_EVENT_ACTION_DOWN) {
-        sp<WindowInfoHandle> foregroundWindowHandle =
-                tempTouchState.getFirstForegroundWindowHandle();
-        if (foregroundWindowHandle &&
-            foregroundWindowHandle->getInfo()->inputConfig.test(
-                    WindowInfo::InputConfig::DUPLICATE_TOUCH_TO_WALLPAPER)) {
-            const std::vector<sp<WindowInfoHandle>>& windowHandles =
-                    getWindowHandlesLocked(displayId);
-            for (const sp<WindowInfoHandle>& windowHandle : windowHandles) {
-                const WindowInfo* info = windowHandle->getInfo();
-                if (info->displayId == displayId &&
-                    windowHandle->getInfo()->inputConfig.test(
-                            WindowInfo::InputConfig::IS_WALLPAPER)) {
-                    BitSet32 pointerIds;
-                    pointerIds.markBit(entry.pointerProperties[0].id);
-                    tempTouchState
-                            .addOrUpdateWindow(windowHandle,
-                                               InputTarget::FLAG_WINDOW_IS_OBSCURED |
-                                                       InputTarget::
-                                                               FLAG_WINDOW_IS_PARTIALLY_OBSCURED |
-                                                       InputTarget::FLAG_DISPATCH_AS_IS,
-                                               pointerIds);
-                }
-            }
-        }
-    }
-
     // Success!  Output targets.
     injectionResult = InputEventInjectionResult::SUCCEEDED;
 
@@ -3685,7 +3679,7 @@
 }
 
 void InputDispatcher::synthesizePointerDownEventsForConnectionLocked(
-        const sp<Connection>& connection) {
+        const sp<Connection>& connection, int32_t targetFlags) {
     if (connection->status == Connection::Status::BROKEN) {
         return;
     }
@@ -3713,7 +3707,7 @@
         target.globalScaleFactor = windowInfo->globalScaleFactor;
     }
     target.inputChannel = connection->inputChannel;
-    target.flags = InputTarget::FLAG_DISPATCH_AS_IS;
+    target.flags = targetFlags;
 
     for (std::unique_ptr<EventEntry>& downEventEntry : downEvents) {
         switch (downEventEntry->type) {
@@ -3744,6 +3738,16 @@
     startDispatchCycleLocked(currentTime, connection);
 }
 
+void InputDispatcher::synthesizeCancelationEventsForWindowLocked(
+        const sp<WindowInfoHandle>& windowHandle, const CancelationOptions& options) {
+    if (windowHandle != nullptr) {
+        sp<Connection> wallpaperConnection = getConnectionLocked(windowHandle->getToken());
+        if (wallpaperConnection != nullptr) {
+            synthesizeCancelationEventsForConnectionLocked(wallpaperConnection, options);
+        }
+    }
+}
+
 std::unique_ptr<MotionEntry> InputDispatcher::splitMotionEvent(
         const MotionEntry& originalMotionEntry, BitSet32 pointerIds) {
     ALOG_ASSERT(pointerIds.value != 0);
@@ -4765,14 +4769,7 @@
                         touchedWindow.windowHandle->getInfo()->inputConfig.test(
                                 gui::WindowInfo::InputConfig::DUPLICATE_TOUCH_TO_WALLPAPER)) {
                         sp<WindowInfoHandle> wallpaper = state.getWallpaperWindow();
-                        if (wallpaper != nullptr) {
-                            sp<Connection> wallpaperConnection =
-                                    getConnectionLocked(wallpaper->getToken());
-                            if (wallpaperConnection != nullptr) {
-                                synthesizeCancelationEventsForConnectionLocked(wallpaperConnection,
-                                                                               options);
-                            }
-                        }
+                        synthesizeCancelationEventsForWindowLocked(wallpaper, options);
                     }
                 }
                 state.windows.erase(state.windows.begin() + i);
@@ -5085,6 +5082,7 @@
         // Erase old window.
         int32_t oldTargetFlags = touchedWindow->targetFlags;
         BitSet32 pointerIds = touchedWindow->pointerIds;
+        sp<WindowInfoHandle> fromWindowHandle = touchedWindow->windowHandle;
         state->removeWindowByToken(fromToken);
 
         // Add new window.
@@ -5116,7 +5114,10 @@
                     options(CancelationOptions::CANCEL_POINTER_EVENTS,
                             "transferring touch focus from this window to another window");
             synthesizeCancelationEventsForConnectionLocked(fromConnection, options);
-            synthesizePointerDownEventsForConnectionLocked(toConnection);
+            synthesizePointerDownEventsForConnectionLocked(toConnection, newTargetFlags);
+            // Check if the wallpaper window should deliver the corresponding event.
+            transferWallpaperTouch(oldTargetFlags, newTargetFlags, fromWindowHandle, toWindowHandle,
+                                   *state, pointerIds);
         }
 
         if (DEBUG_FOCUS) {
@@ -6401,4 +6402,97 @@
     mMonitorDispatchingTimeout = timeout;
 }
 
+void InputDispatcher::slipWallpaperTouch(int32_t targetFlags,
+                                         const sp<WindowInfoHandle>& oldWindowHandle,
+                                         const sp<WindowInfoHandle>& newWindowHandle,
+                                         TouchState& state, const BitSet32& pointerIds) {
+    const bool oldHasWallpaper = oldWindowHandle->getInfo()->inputConfig.test(
+            gui::WindowInfo::InputConfig::DUPLICATE_TOUCH_TO_WALLPAPER);
+    const bool newHasWallpaper = (targetFlags & InputTarget::FLAG_FOREGROUND) &&
+            newWindowHandle->getInfo()->inputConfig.test(
+                    gui::WindowInfo::InputConfig::DUPLICATE_TOUCH_TO_WALLPAPER);
+    const sp<WindowInfoHandle> oldWallpaper =
+            oldHasWallpaper ? state.getWallpaperWindow() : nullptr;
+    const sp<WindowInfoHandle> newWallpaper =
+            newHasWallpaper ? findWallpaperWindowBelow(newWindowHandle) : nullptr;
+    if (oldWallpaper == newWallpaper) {
+        return;
+    }
+
+    if (oldWallpaper != nullptr) {
+        state.addOrUpdateWindow(oldWallpaper, InputTarget::FLAG_DISPATCH_AS_SLIPPERY_EXIT,
+                                BitSet32(0));
+    }
+
+    if (newWallpaper != nullptr) {
+        state.addOrUpdateWindow(newWallpaper,
+                                InputTarget::FLAG_DISPATCH_AS_SLIPPERY_ENTER |
+                                        InputTarget::FLAG_WINDOW_IS_OBSCURED |
+                                        InputTarget::FLAG_WINDOW_IS_PARTIALLY_OBSCURED,
+                                pointerIds);
+    }
+}
+
+void InputDispatcher::transferWallpaperTouch(int32_t oldTargetFlags, int32_t newTargetFlags,
+                                             const sp<WindowInfoHandle> fromWindowHandle,
+                                             const sp<WindowInfoHandle> toWindowHandle,
+                                             TouchState& state, const BitSet32& pointerIds) {
+    const bool oldHasWallpaper = (oldTargetFlags & InputTarget::FLAG_FOREGROUND) &&
+            fromWindowHandle->getInfo()->inputConfig.test(
+                    gui::WindowInfo::InputConfig::DUPLICATE_TOUCH_TO_WALLPAPER);
+    const bool newHasWallpaper = (newTargetFlags & InputTarget::FLAG_FOREGROUND) &&
+            toWindowHandle->getInfo()->inputConfig.test(
+                    gui::WindowInfo::InputConfig::DUPLICATE_TOUCH_TO_WALLPAPER);
+
+    const sp<WindowInfoHandle> oldWallpaper =
+            oldHasWallpaper ? state.getWallpaperWindow() : nullptr;
+    const sp<WindowInfoHandle> newWallpaper =
+            newHasWallpaper ? findWallpaperWindowBelow(toWindowHandle) : nullptr;
+    if (oldWallpaper == newWallpaper) {
+        return;
+    }
+
+    if (oldWallpaper != nullptr) {
+        CancelationOptions options(CancelationOptions::Mode::CANCEL_POINTER_EVENTS,
+                                   "transferring touch focus to another window");
+        state.removeWindowByToken(oldWallpaper->getToken());
+        synthesizeCancelationEventsForWindowLocked(oldWallpaper, options);
+    }
+
+    if (newWallpaper != nullptr) {
+        int32_t wallpaperFlags =
+                oldTargetFlags & (InputTarget::FLAG_SPLIT | InputTarget::FLAG_DISPATCH_AS_IS);
+        wallpaperFlags |= InputTarget::FLAG_WINDOW_IS_OBSCURED |
+                InputTarget::FLAG_WINDOW_IS_PARTIALLY_OBSCURED;
+        state.addOrUpdateWindow(newWallpaper, wallpaperFlags, pointerIds);
+        sp<Connection> wallpaperConnection = getConnectionLocked(newWallpaper->getToken());
+        if (wallpaperConnection != nullptr) {
+            sp<Connection> toConnection = getConnectionLocked(toWindowHandle->getToken());
+            toConnection->inputState.mergePointerStateTo(wallpaperConnection->inputState);
+            synthesizePointerDownEventsForConnectionLocked(wallpaperConnection, wallpaperFlags);
+        }
+    }
+}
+
+sp<WindowInfoHandle> InputDispatcher::findWallpaperWindowBelow(
+        const sp<WindowInfoHandle>& windowHandle) const {
+    const std::vector<sp<WindowInfoHandle>>& windowHandles =
+            getWindowHandlesLocked(windowHandle->getInfo()->displayId);
+    bool foundWindow = false;
+    for (const sp<WindowInfoHandle>& otherHandle : windowHandles) {
+        if (!foundWindow && otherHandle != windowHandle) {
+            continue;
+        }
+        if (windowHandle == otherHandle) {
+            foundWindow = true;
+            continue;
+        }
+
+        if (otherHandle->getInfo()->inputConfig.test(WindowInfo::InputConfig::IS_WALLPAPER)) {
+            return otherHandle;
+        }
+    }
+    return nullptr;
+}
+
 } // namespace android::inputdispatcher
diff --git a/services/inputflinger/dispatcher/InputDispatcher.h b/services/inputflinger/dispatcher/InputDispatcher.h
index ed89ed0..0df5894 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.h
+++ b/services/inputflinger/dispatcher/InputDispatcher.h
@@ -621,8 +621,12 @@
                                                         const CancelationOptions& options)
             REQUIRES(mLock);
 
-    void synthesizePointerDownEventsForConnectionLocked(const sp<Connection>& connection)
-            REQUIRES(mLock);
+    void synthesizePointerDownEventsForConnectionLocked(const sp<Connection>& connection,
+                                                        int32_t targetFlags) REQUIRES(mLock);
+
+    void synthesizeCancelationEventsForWindowLocked(
+            const sp<android::gui::WindowInfoHandle>& windowHandle,
+            const CancelationOptions& options) REQUIRES(mLock);
 
     // Splitting motion events across windows.
     std::unique_ptr<MotionEntry> splitMotionEvent(const MotionEntry& originalMotionEntry,
@@ -684,6 +688,18 @@
     bool recentWindowsAreOwnedByLocked(int32_t pid, int32_t uid) REQUIRES(mLock);
 
     sp<InputReporterInterface> mReporter;
+
+    void slipWallpaperTouch(int32_t targetFlags,
+                            const sp<android::gui::WindowInfoHandle>& oldWindowHandle,
+                            const sp<android::gui::WindowInfoHandle>& newWindowHandle,
+                            TouchState& state, const BitSet32& pointerIds) REQUIRES(mLock);
+    void transferWallpaperTouch(int32_t oldTargetFlags, int32_t newTargetFlags,
+                                const sp<android::gui::WindowInfoHandle> fromWindowHandle,
+                                const sp<android::gui::WindowInfoHandle> toWindowHandle,
+                                TouchState& state, const BitSet32& pointerIds) REQUIRES(mLock);
+
+    sp<android::gui::WindowInfoHandle> findWallpaperWindowBelow(
+            const sp<android::gui::WindowInfoHandle>& windowHandle) const REQUIRES(mLock);
 };
 
 } // namespace android::inputdispatcher
diff --git a/services/inputflinger/tests/InputDispatcher_test.cpp b/services/inputflinger/tests/InputDispatcher_test.cpp
index fce0f99..b2575fe 100644
--- a/services/inputflinger/tests/InputDispatcher_test.cpp
+++ b/services/inputflinger/tests/InputDispatcher_test.cpp
@@ -58,6 +58,8 @@
         AMOTION_EVENT_ACTION_POINTER_DOWN | (1 << AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT);
 static constexpr int32_t POINTER_2_DOWN =
         AMOTION_EVENT_ACTION_POINTER_DOWN | (2 << AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT);
+static constexpr int32_t POINTER_0_UP =
+        AMOTION_EVENT_ACTION_POINTER_UP | (0 << AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT);
 static constexpr int32_t POINTER_1_UP =
         AMOTION_EVENT_ACTION_POINTER_UP | (1 << AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT);
 
@@ -73,6 +75,9 @@
 
 static constexpr std::chrono::duration STALE_EVENT_TIMEOUT = 1000ms;
 
+static constexpr int expectedWallpaperFlags =
+        AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED | AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED;
+
 struct PointF {
     float x;
     float y;
@@ -1670,8 +1675,6 @@
     sp<FakeWindowHandle> wallpaperWindow =
             new FakeWindowHandle(application, mDispatcher, "Wallpaper", ADISPLAY_ID_DEFAULT);
     wallpaperWindow->setIsWallpaper(true);
-    constexpr int expectedWallpaperFlags =
-            AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED | AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED;
 
     mDispatcher->setInputWindows({{ADISPLAY_ID_DEFAULT, {foregroundWindow, wallpaperWindow}}});
     ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
@@ -1714,8 +1717,6 @@
     sp<FakeWindowHandle> wallpaperWindow =
             new FakeWindowHandle(application, mDispatcher, "Wallpaper", ADISPLAY_ID_DEFAULT);
     wallpaperWindow->setIsWallpaper(true);
-    constexpr int expectedWallpaperFlags =
-            AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED | AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED;
 
     mDispatcher->setInputWindows({{ADISPLAY_ID_DEFAULT, {foregroundWindow, wallpaperWindow}}});
     ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
@@ -1745,24 +1746,27 @@
     foregroundWindow->consumeMotionCancel();
 }
 
+class ShouldSplitTouchFixture : public InputDispatcherTest,
+                                public ::testing::WithParamInterface<bool> {};
+INSTANTIATE_TEST_SUITE_P(InputDispatcherTest, ShouldSplitTouchFixture,
+                         ::testing::Values(true, false));
 /**
  * A single window that receives touch (on top), and a wallpaper window underneath it.
  * The top window gets a multitouch gesture.
  * Ensure that wallpaper gets the same gesture.
  */
-TEST_F(InputDispatcherTest, WallpaperWindow_ReceivesMultiTouch) {
+TEST_P(ShouldSplitTouchFixture, WallpaperWindowReceivesMultiTouch) {
     std::shared_ptr<FakeApplicationHandle> application = std::make_shared<FakeApplicationHandle>();
-    sp<FakeWindowHandle> window =
-            new FakeWindowHandle(application, mDispatcher, "Top", ADISPLAY_ID_DEFAULT);
-    window->setDupTouchToWallpaper(true);
+    sp<FakeWindowHandle> foregroundWindow =
+            new FakeWindowHandle(application, mDispatcher, "Foreground", ADISPLAY_ID_DEFAULT);
+    foregroundWindow->setDupTouchToWallpaper(true);
+    foregroundWindow->setPreventSplitting(GetParam());
 
     sp<FakeWindowHandle> wallpaperWindow =
             new FakeWindowHandle(application, mDispatcher, "Wallpaper", ADISPLAY_ID_DEFAULT);
     wallpaperWindow->setIsWallpaper(true);
-    constexpr int expectedWallpaperFlags =
-            AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED | AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED;
 
-    mDispatcher->setInputWindows({{ADISPLAY_ID_DEFAULT, {window, wallpaperWindow}}});
+    mDispatcher->setInputWindows({{ADISPLAY_ID_DEFAULT, {foregroundWindow, wallpaperWindow}}});
 
     // Touch down on top window
     ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
@@ -1771,7 +1775,7 @@
             << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
 
     // Both top window and its wallpaper should receive the touch down
-    window->consumeMotionDown();
+    foregroundWindow->consumeMotionDown();
     wallpaperWindow->consumeMotionDown(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
 
     // Second finger down on the top window
@@ -1790,11 +1794,34 @@
                                 InputEventInjectionSync::WAIT_FOR_RESULT))
             << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
 
-    window->consumeMotionPointerDown(1 /* pointerIndex */);
+    foregroundWindow->consumeMotionPointerDown(1 /* pointerIndex */);
     wallpaperWindow->consumeMotionPointerDown(1 /* pointerIndex */, ADISPLAY_ID_DEFAULT,
                                               expectedWallpaperFlags);
-    window->assertNoEvents();
-    wallpaperWindow->assertNoEvents();
+
+    const MotionEvent secondFingerUpEvent =
+            MotionEventBuilder(POINTER_0_UP, AINPUT_SOURCE_TOUCHSCREEN)
+                    .displayId(ADISPLAY_ID_DEFAULT)
+                    .eventTime(systemTime(SYSTEM_TIME_MONOTONIC))
+                    .pointer(PointerBuilder(/* id */ 0, AMOTION_EVENT_TOOL_TYPE_FINGER)
+                                     .x(100)
+                                     .y(100))
+                    .pointer(PointerBuilder(/* id */ 1, AMOTION_EVENT_TOOL_TYPE_FINGER)
+                                     .x(150)
+                                     .y(150))
+                    .build();
+    ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
+              injectMotionEvent(mDispatcher, secondFingerUpEvent, INJECT_EVENT_TIMEOUT,
+                                InputEventInjectionSync::WAIT_FOR_RESULT))
+            << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
+    foregroundWindow->consumeMotionPointerUp(0);
+    wallpaperWindow->consumeMotionPointerUp(0, ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
+
+    ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
+              injectMotionUp(mDispatcher, AINPUT_SOURCE_TOUCHSCREEN, ADISPLAY_ID_DEFAULT,
+                             {100, 100}))
+            << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
+    foregroundWindow->consumeMotionUp(ADISPLAY_ID_DEFAULT);
+    wallpaperWindow->consumeMotionUp(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
 }
 
 /**
@@ -1821,8 +1848,6 @@
             new FakeWindowHandle(application, mDispatcher, "Wallpaper", ADISPLAY_ID_DEFAULT);
     wallpaperWindow->setFrame(Rect(0, 0, 400, 200));
     wallpaperWindow->setIsWallpaper(true);
-    constexpr int expectedWallpaperFlags =
-            AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED | AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED;
 
     mDispatcher->setInputWindows(
             {{ADISPLAY_ID_DEFAULT, {leftWindow, rightWindow, wallpaperWindow}}});
@@ -1887,62 +1912,49 @@
     wallpaperWindow->assertNoEvents();
 }
 
-TEST_F(InputDispatcherTest, WallpaperWindowReceivesMultiTouch) {
+/**
+ * Two windows: a window on the left with dup touch to wallpaper and window on the right without it.
+ * The touch slips to the right window. so left window and wallpaper should receive ACTION_CANCEL
+ * The right window should receive ACTION_DOWN.
+ */
+TEST_F(InputDispatcherTest, WallpaperWindowWhenSlippery) {
     std::shared_ptr<FakeApplicationHandle> application = std::make_shared<FakeApplicationHandle>();
-    sp<FakeWindowHandle> window =
-            sp<FakeWindowHandle>::make(application, mDispatcher, "Top", ADISPLAY_ID_DEFAULT);
-    window->setDupTouchToWallpaper(true);
+    sp<FakeWindowHandle> leftWindow =
+            new FakeWindowHandle(application, mDispatcher, "Left", ADISPLAY_ID_DEFAULT);
+    leftWindow->setFrame(Rect(0, 0, 200, 200));
+    leftWindow->setDupTouchToWallpaper(true);
+    leftWindow->setSlippery(true);
+
+    sp<FakeWindowHandle> rightWindow =
+            new FakeWindowHandle(application, mDispatcher, "Right", ADISPLAY_ID_DEFAULT);
+    rightWindow->setFrame(Rect(200, 0, 400, 200));
 
     sp<FakeWindowHandle> wallpaperWindow =
-            sp<FakeWindowHandle>::make(application, mDispatcher, "Wallpaper", ADISPLAY_ID_DEFAULT);
+            new FakeWindowHandle(application, mDispatcher, "Wallpaper", ADISPLAY_ID_DEFAULT);
     wallpaperWindow->setIsWallpaper(true);
-    constexpr int expectedWallpaperFlags =
-            AMOTION_EVENT_FLAG_WINDOW_IS_OBSCURED | AMOTION_EVENT_FLAG_WINDOW_IS_PARTIALLY_OBSCURED;
-    wallpaperWindow->setPreventSplitting(true);
 
-    mDispatcher->setInputWindows({{ADISPLAY_ID_DEFAULT, {window, wallpaperWindow}}});
+    mDispatcher->setInputWindows(
+            {{ADISPLAY_ID_DEFAULT, {leftWindow, rightWindow, wallpaperWindow}}});
 
+    // Touch down on left window
     ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
               injectMotionDown(mDispatcher, AINPUT_SOURCE_TOUCHSCREEN, ADISPLAY_ID_DEFAULT,
-                               {50, 50}))
+                               {100, 100}))
             << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
-    window->consumeMotionDown(ADISPLAY_ID_DEFAULT);
+
+    // Both foreground window and its wallpaper should receive the touch down
+    leftWindow->consumeMotionDown();
     wallpaperWindow->consumeMotionDown(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
 
-    const MotionEvent secondFingerDownEvent =
-            MotionEventBuilder(POINTER_1_DOWN, AINPUT_SOURCE_TOUCHSCREEN)
-                    .displayId(ADISPLAY_ID_DEFAULT)
-                    .eventTime(systemTime(SYSTEM_TIME_MONOTONIC))
-                    .pointer(PointerBuilder(/* id */ 0, AMOTION_EVENT_TOOL_TYPE_FINGER).x(50).y(50))
-                    .pointer(PointerBuilder(/* id */ 1, AMOTION_EVENT_TOOL_TYPE_FINGER).x(10).y(10))
-                    .build();
+    // Move to right window, the left window should receive cancel.
     ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
-              injectMotionEvent(mDispatcher, secondFingerDownEvent, INJECT_EVENT_TIMEOUT,
-                                InputEventInjectionSync::WAIT_FOR_RESULT))
+              injectMotionEvent(mDispatcher, AMOTION_EVENT_ACTION_MOVE, AINPUT_SOURCE_TOUCHSCREEN,
+                                ADISPLAY_ID_DEFAULT, {201, 100}))
             << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
 
-    window->consumeMotionPointerDown(1);
-    wallpaperWindow->consumeMotionPointerDown(1, ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
-
-    const MotionEvent secondFingerUpEvent =
-            MotionEventBuilder(POINTER_1_UP, AINPUT_SOURCE_TOUCHSCREEN)
-                    .displayId(ADISPLAY_ID_DEFAULT)
-                    .eventTime(systemTime(SYSTEM_TIME_MONOTONIC))
-                    .pointer(PointerBuilder(/* id */ 0, AMOTION_EVENT_TOOL_TYPE_FINGER).x(50).y(50))
-                    .pointer(PointerBuilder(/* id */ 1, AMOTION_EVENT_TOOL_TYPE_FINGER).x(10).y(10))
-                    .build();
-    ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
-              injectMotionEvent(mDispatcher, secondFingerUpEvent, INJECT_EVENT_TIMEOUT,
-                                InputEventInjectionSync::WAIT_FOR_RESULT))
-            << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
-    window->consumeMotionPointerUp(1);
-    wallpaperWindow->consumeMotionPointerUp(1, ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
-
-    ASSERT_EQ(InputEventInjectionResult::SUCCEEDED,
-              injectMotionUp(mDispatcher, AINPUT_SOURCE_TOUCHSCREEN, ADISPLAY_ID_DEFAULT, {50, 50}))
-            << "Inject motion event should return InputEventInjectionResult::SUCCEEDED";
-    window->consumeMotionUp(ADISPLAY_ID_DEFAULT);
-    wallpaperWindow->consumeMotionUp(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
+    leftWindow->consumeMotionCancel();
+    rightWindow->consumeMotionDown(ADISPLAY_ID_DEFAULT);
+    wallpaperWindow->consumeMotionCancel(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
 }
 
 /**
@@ -2620,20 +2632,26 @@
     // Create a couple of windows
     sp<FakeWindowHandle> firstWindow =
             new FakeWindowHandle(application, mDispatcher, "First Window", ADISPLAY_ID_DEFAULT);
+    firstWindow->setDupTouchToWallpaper(true);
+
     sp<FakeWindowHandle> secondWindow =
             new FakeWindowHandle(application, mDispatcher, "Second Window", ADISPLAY_ID_DEFAULT);
-
+    sp<FakeWindowHandle> wallpaper =
+            new FakeWindowHandle(application, mDispatcher, "Wallpaper", ADISPLAY_ID_DEFAULT);
+    wallpaper->setIsWallpaper(true);
     // Add the windows to the dispatcher
-    mDispatcher->setInputWindows({{ADISPLAY_ID_DEFAULT, {firstWindow, secondWindow}}});
+    mDispatcher->setInputWindows({{ADISPLAY_ID_DEFAULT, {firstWindow, secondWindow, wallpaper}}});
 
     // Send down to the first window
     NotifyMotionArgs downMotionArgs =
             generateMotionArgs(AMOTION_EVENT_ACTION_DOWN, AINPUT_SOURCE_TOUCHSCREEN,
                                ADISPLAY_ID_DEFAULT);
     mDispatcher->notifyMotion(&downMotionArgs);
+
     // Only the first window should get the down event
     firstWindow->consumeMotionDown();
     secondWindow->assertNoEvents();
+    wallpaper->consumeMotionDown(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
 
     // Transfer touch to the second window
     TransferFunction f = GetParam();
@@ -2642,6 +2660,7 @@
     // The first window gets cancel and the second gets down
     firstWindow->consumeMotionCancel();
     secondWindow->consumeMotionDown();
+    wallpaper->consumeMotionCancel(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
 
     // Send up event to the second window
     NotifyMotionArgs upMotionArgs =
@@ -2651,6 +2670,7 @@
     // The first  window gets no events and the second gets up
     firstWindow->assertNoEvents();
     secondWindow->consumeMotionUp();
+    wallpaper->assertNoEvents();
 }
 
 /**
@@ -2772,6 +2792,65 @@
     secondWindow->consumeMotionUp();
 }
 
+TEST_P(TransferTouchFixture, TransferTouch_MultipleWallpapers) {
+    std::shared_ptr<FakeApplicationHandle> application = std::make_shared<FakeApplicationHandle>();
+
+    // Create a couple of windows
+    sp<FakeWindowHandle> firstWindow =
+            sp<FakeWindowHandle>::make(application, mDispatcher, "First Window",
+                                       ADISPLAY_ID_DEFAULT);
+    firstWindow->setDupTouchToWallpaper(true);
+    sp<FakeWindowHandle> secondWindow =
+            sp<FakeWindowHandle>::make(application, mDispatcher, "Second Window",
+                                       ADISPLAY_ID_DEFAULT);
+    secondWindow->setDupTouchToWallpaper(true);
+
+    sp<FakeWindowHandle> wallpaper1 =
+            sp<FakeWindowHandle>::make(application, mDispatcher, "Wallpaper1", ADISPLAY_ID_DEFAULT);
+    wallpaper1->setIsWallpaper(true);
+
+    sp<FakeWindowHandle> wallpaper2 =
+            sp<FakeWindowHandle>::make(application, mDispatcher, "Wallpaper2", ADISPLAY_ID_DEFAULT);
+    wallpaper2->setIsWallpaper(true);
+    // Add the windows to the dispatcher
+    mDispatcher->setInputWindows(
+            {{ADISPLAY_ID_DEFAULT, {firstWindow, wallpaper1, secondWindow, wallpaper2}}});
+
+    // Send down to the first window
+    NotifyMotionArgs downMotionArgs =
+            generateMotionArgs(AMOTION_EVENT_ACTION_DOWN, AINPUT_SOURCE_TOUCHSCREEN,
+                               ADISPLAY_ID_DEFAULT);
+    mDispatcher->notifyMotion(&downMotionArgs);
+
+    // Only the first window should get the down event
+    firstWindow->consumeMotionDown();
+    secondWindow->assertNoEvents();
+    wallpaper1->consumeMotionDown(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
+    wallpaper2->assertNoEvents();
+
+    // Transfer touch focus to the second window
+    TransferFunction f = GetParam();
+    bool success = f(mDispatcher, firstWindow->getToken(), secondWindow->getToken());
+    ASSERT_TRUE(success);
+
+    // The first window gets cancel and the second gets down
+    firstWindow->consumeMotionCancel();
+    secondWindow->consumeMotionDown();
+    wallpaper1->consumeMotionCancel(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
+    wallpaper2->consumeMotionDown(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
+
+    // Send up event to the second window
+    NotifyMotionArgs upMotionArgs =
+            generateMotionArgs(AMOTION_EVENT_ACTION_UP, AINPUT_SOURCE_TOUCHSCREEN,
+                               ADISPLAY_ID_DEFAULT);
+    mDispatcher->notifyMotion(&upMotionArgs);
+    // The first  window gets no events and the second gets up
+    firstWindow->assertNoEvents();
+    secondWindow->consumeMotionUp();
+    wallpaper1->assertNoEvents();
+    wallpaper2->consumeMotionUp(ADISPLAY_ID_DEFAULT, expectedWallpaperFlags);
+}
+
 // For the cases of single pointer touch and two pointers non-split touch, the api's
 // 'transferTouch' and 'transferTouchFocus' are equivalent in behaviour. They only differ
 // for the case where there are multiple pointers split across several windows.