Bug 1193062 - Add mHandledByAPZ on PanGestureInput and ScrollWheelInput, and sync the information to the WidgetWheelEvent. r=kats

--HG--
extra : commitid : 2qlm0ULac3
extra : rebase_source : 52fc5d3930a9b3a941f7e3665ef6b371e8a4b1b5
extra : histedit_source : d99996a3729a1bc78b9f4631f950476321f93c1f

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -554,6 +554,33 @@ APZCTreeManager::UpdateHitTestingTree(TreeBuildingState& aState,
   return node;
 }
 
+// Returns whether or not a wheel event action will be (or was) performed by
+// APZ. If this returns true, the event must not perform a synchronous
+// scroll.
+//
+// Even if this returns false, all wheel events in APZ-aware widgets must
+// be sent through APZ so they are transformed correctly for TabParent.
+static bool
+WillHandleWheelEvent(WidgetWheelEvent* aEvent)
+{
+  return EventStateManager::WheelEventIsScrollAction(aEvent) &&
+         (aEvent->deltaMode == nsIDOMWheelEvent::DOM_DELTA_LINE
+            || aEvent->deltaMode == nsIDOMWheelEvent::DOM_DELTA_PIXEL) &&
+         !EventStateManager::WheelEventNeedsDeltaMultipliers(aEvent);
+}
+
+template<typename PanGestureOrScrollWheelInput>
+static bool
+WillHandleInput(const PanGestureOrScrollWheelInput& aPanInput)
+{
+  if (!NS_IsMainThread()) {
+    return true;
+  }
+
+  WidgetWheelEvent wheelEvent = aPanInput.ToWidgetWheelEvent(nullptr);
+  return WillHandleWheelEvent(&wheelEvent);
+}
+
 void
 APZCTreeManager::FlushApzRepaints(uint64_t aLayersId)
 {
@@ -591,6 +618,12 @@ APZCTreeManager::ReceiveInputEvent(InputData& aEvent,
       FlushRepaintsToClearScreenToGeckoTransform();
 
       ScrollWheelInput& wheelInput = aEvent.AsScrollWheelInput();
+
+      wheelInput.mHandledByAPZ = WillHandleInput(wheelInput);
+      if (!wheelInput.mHandledByAPZ) {
+        return result;
+      }
+
       nsRefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(wheelInput.mOrigin,
                                                             &hitResult);
       if (apzc) {
@@ -623,6 +656,11 @@ APZCTreeManager::ReceiveInputEvent(InputData& aEvent,
       FlushRepaintsToClearScreenToGeckoTransform();
 
       PanGestureInput& panInput = aEvent.AsPanGestureInput();
+      panInput.mHandledByAPZ = WillHandleInput(panInput);
+      if (!panInput.mHandledByAPZ) {
+        return result;
+      }
+
       nsRefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(panInput.mPanStartPoint,
                                                             &hitResult);
       if (apzc) {
@@ -914,25 +952,10 @@ APZCTreeManager::ProcessWheelEvent(WidgetWheelEvent& aEvent,
   nsEventStatus status = ReceiveInputEvent(input, aOutTargetGuid, aOutInputBlockId);
   aEvent.refPoint.x = input.mOrigin.x;
   aEvent.refPoint.y = input.mOrigin.y;
-  aEvent.mFlags.mHandledByAPZ = true;
+  aEvent.mFlags.mHandledByAPZ = input.mHandledByAPZ;
   return status;
 }
 
-// Returns whether or not a wheel event action will be (or was) performed by
-// APZ. If this returns true, the event must not perform a synchronous
-// scroll.
-//
-// Even if this returns false, all wheel events in APZ-aware widgets must
-// be sent through APZ so they are transformed correctly for TabParent.
-static bool
-WillHandleWheelEvent(WidgetWheelEvent* aEvent)
-{
-  return EventStateManager::WheelEventIsScrollAction(aEvent) &&
-         (aEvent->deltaMode == nsIDOMWheelEvent::DOM_DELTA_LINE
-            || aEvent->deltaMode == nsIDOMWheelEvent::DOM_DELTA_PIXEL) &&
-         !EventStateManager::WheelEventNeedsDeltaMultipliers(aEvent);
-}
-
 nsEventStatus
 APZCTreeManager::ReceiveInputEvent(WidgetInputEvent& aEvent,
                                    ScrollableLayerGuid* aOutTargetGuid,
@@ -970,12 +993,10 @@ APZCTreeManager::ReceiveInputEvent(WidgetInputEvent& aEvent,
     }
     case eWheelEventClass: {
       WidgetWheelEvent& wheelEvent = *aEvent.AsWheelEvent();
-      if (!WillHandleWheelEvent(&wheelEvent)) {
-        // Don't send through APZ if we're not scrolling or if the delta mode
-        // is not line-based.
-        return ProcessEvent(aEvent, aOutTargetGuid, aOutInputBlockId);
+      if (WillHandleWheelEvent(&wheelEvent)) {
+        return ProcessWheelEvent(wheelEvent, aOutTargetGuid, aOutInputBlockId);
       }
-      return ProcessWheelEvent(wheelEvent, aOutTargetGuid, aOutInputBlockId);
+      return ProcessEvent(aEvent, aOutTargetGuid, aOutInputBlockId);
     }
     default: {
       return ProcessEvent(aEvent, aOutTargetGuid, aOutInputBlockId);

widget/InputData.cpp

@@ -255,7 +255,7 @@ PanGestureInput::ToWidgetWheelEvent(nsIWidget* aWidget) const
   wheelEvent.lineOrPageDeltaY = mLineOrPageDeltaY;
   wheelEvent.deltaX = mPanDisplacement.x;
   wheelEvent.deltaY = mPanDisplacement.y;
-  wheelEvent.mFlags.mHandledByAPZ = true;
+  wheelEvent.mFlags.mHandledByAPZ = mHandledByAPZ;
   return wheelEvent;
 }
 
@@ -327,7 +327,7 @@ ScrollWheelInput::ToWidgetWheelEvent(nsIWidget* aWidget) const
   wheelEvent.deltaY = mDeltaY;
   wheelEvent.lineOrPageDeltaX = mLineOrPageDeltaX;
   wheelEvent.lineOrPageDeltaY = mLineOrPageDeltaY;
-  wheelEvent.mFlags.mHandledByAPZ = true;
+  wheelEvent.mFlags.mHandledByAPZ = mHandledByAPZ;
   return wheelEvent;
 }
 

widget/InputData.h

@@ -309,7 +309,8 @@ public:
       mPanStartPoint(aPanStartPoint),
       mPanDisplacement(aPanDisplacement),
       mLineOrPageDeltaX(0),
-      mLineOrPageDeltaY(0)
+      mLineOrPageDeltaY(0),
+      mHandledByAPZ(false)
   {
   }
 
@@ -333,6 +334,8 @@ public:
   // See lineOrPageDeltaX/Y on WidgetWheelEvent.
   int32_t mLineOrPageDeltaX;
   int32_t mLineOrPageDeltaY;
+
+  bool mHandledByAPZ;
 };
 
 /**
@@ -512,6 +515,7 @@ public:
      mDeltaType(aDeltaType),
      mScrollMode(aScrollMode),
      mOrigin(aOrigin),
+     mHandledByAPZ(false),
      mDeltaX(aDeltaX),
      mDeltaY(aDeltaY),
      mLineOrPageDeltaX(0),
@@ -526,6 +530,8 @@ public:
   ScrollMode mScrollMode;
   ScreenPoint mOrigin;
 
+  bool mHandledByAPZ;
+
   // Deltas are in units corresponding to the delta type. For line deltas, they
   // are the number of line units to scroll. The number of device pixels for a
   // horizontal and vertical line unit are in FrameMetrics::mLineScrollAmount.