Bug 1039979 - When cancelling animations based on user input, cancel animations on the entire handoff chain. r=botond

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -888,16 +888,26 @@ bool
 APZCTreeManager::FlushRepaintsForOverscrollHandoffChain()
 {
   MonitorAutoLock lock(mTreeLock);  // to access mOverscrollHandoffChain
-  if (mOverscrollHandoffChain.length() == 0) {
-    return false;
-  }
   for (uint32_t i = 0; i < mOverscrollHandoffChain.length(); i++) {
     nsRefPtr<AsyncPanZoomController> item = mOverscrollHandoffChain[i];
     if (item) {
       item->FlushRepaintForOverscrollHandoff();
     }
   }
-  return true;
+  return mOverscrollHandoffChain.length() > 0;
+}
+
+bool
+APZCTreeManager::CancelAnimationsForOverscrollHandoffChain()
+{
+  MonitorAutoLock lock(mTreeLock);  // to access mOverscrollHandoffChain
+  for (uint32_t i = 0; i < mOverscrollHandoffChain.length(); i++) {
+    nsRefPtr<AsyncPanZoomController> item = mOverscrollHandoffChain[i];
+    if (item) {
+      item->CancelAnimation();
+    }
+  }
+  return mOverscrollHandoffChain.length() > 0;
 }
 
 bool

gfx/layers/apz/src/APZCTreeManager.h

@@ -293,6 +293,7 @@ public:
   bool HandOffFling(AsyncPanZoomController* aApzc, ScreenPoint aVelocity);
 
   bool FlushRepaintsForOverscrollHandoffChain();
+  bool CancelAnimationsForOverscrollHandoffChain();
 
   /**
    * Determine whether |aApzc|, or any APZC along its overscroll handoff chain,

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -813,6 +813,18 @@ AsyncPanZoomController::GetTouchStartTolerance()
   return static_cast<AxisLockMode>(gfxPrefs::APZAxisLockMode());
 }
 
+void
+AsyncPanZoomController::CancelAnimationForHandoffChain()
+{
+  APZCTreeManager* treeManagerLocal = mTreeManager;
+  if (treeManagerLocal && treeManagerLocal->CancelAnimationsForOverscrollHandoffChain()) {
+    return;
+  }
+  NS_WARNING("Overscroll handoff chain was empty in CancelAnimationForHandoffChain! This should not be the case.");
+  // Graceful handling of error condition
+  CancelAnimation();
+}
+
 nsEventStatus AsyncPanZoomController::ReceiveInputEvent(const InputData& aEvent) {
   AssertOnControllerThread();
 
@@ -830,7 +842,7 @@ nsEventStatus AsyncPanZoomController::ReceiveInputEvent(const InputData& aEvent)
       ScheduleContentResponseTimeout();
       // However, we still want to cancel animations here because a finger has gone down
       // and we don't want to keep moving the content under the finger.
-      CancelAnimation();
+      CancelAnimationForHandoffChain();
     } else {
       // Content won't prevent-default this, so we can just pretend like we scheduled
       // a timeout and it expired. Note that we will still receive a ContentReceivedTouch
@@ -967,7 +979,7 @@ nsEventStatus AsyncPanZoomController::OnTouchStart(const MultiTouchInput& aEvent
       }
       // Fall through.
     case ANIMATING_ZOOM:
-      CancelAnimation();
+      CancelAnimationForHandoffChain();
       // Fall through.
     case NOTHING: {
       mX.StartTouch(point.x, aEvent.mTime);
@@ -1293,7 +1305,7 @@ nsEventStatus AsyncPanZoomController::OnPanMayBegin(const PanGestureInput& aEven
 
   mX.StartTouch(aEvent.mPanStartPoint.x, aEvent.mTime);
   mY.StartTouch(aEvent.mPanStartPoint.y, aEvent.mTime);
-  CancelAnimation();
+  CancelAnimationForHandoffChain();
 
   return nsEventStatus_eConsumeNoDefault;
 }

gfx/layers/apz/src/AsyncPanZoomController.h

@@ -536,6 +536,12 @@ protected:
   void FireAsyncScrollOnTimeout();
 
 private:
+  /**
+   * Cancel animations all the way up the overscroll handoff chain if possible,
+   * or just the local APZC if not.
+   */
+  void CancelAnimationForHandoffChain();
+
   /**
    * Helper to set the current state. Holds the monitor before actually setting
    * it and fires content controller events based on state changes. Always set