Bug 1105109 - Have APZCTreeManager keep track of the current mouse position. r=kats

MozReview-Commit-ID: 7o80O8rpdNS

--HG--
extra : rebase_source : c775d1d2f245878e10774e41b58d550eabb77d18

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -986,6 +986,8 @@ APZCTreeManager::ReceiveInputEvent(InputData& aEvent,
       MouseInput& mouseInput = aEvent.AsMouseInput();
       mouseInput.mHandledByAPZ = true;
 
+      mCurrentMousePosition = mouseInput.mOrigin;
+
       bool startsDrag = DragTracker::StartsDrag(mouseInput);
       if (startsDrag) {
         // If this is the start of a drag we need to unambiguously know if it's
@@ -2478,6 +2480,12 @@ APZCTreeManager::GetApzcToGeckoTransform(const AsyncPanZoomController *aApzc) co
   return ViewAs<ParentLayerToScreenMatrix4x4>(result);
 }
 
+ScreenPoint
+APZCTreeManager::GetCurrentMousePosition() const
+{
+  return mCurrentMousePosition;
+}
+
 already_AddRefed<AsyncPanZoomController>
 APZCTreeManager::GetMultitouchTarget(AsyncPanZoomController* aApzc1, AsyncPanZoomController* aApzc2) const
 {

gfx/layers/apz/src/APZCTreeManager.h

@@ -485,6 +485,7 @@ public:
                                                          const FrameMetrics::ViewID& aScrollId);
   ScreenToParentLayerMatrix4x4 GetScreenToApzcTransform(const AsyncPanZoomController *aApzc) const;
   ParentLayerToScreenMatrix4x4 GetApzcToGeckoTransform(const AsyncPanZoomController *aApzc) const;
+  ScreenPoint GetCurrentMousePosition() const;
 
   /**
    * Process touch velocity.
@@ -597,6 +598,9 @@ private:
   /* Tracks the number of touch points we are tracking that are currently on
    * the screen. */
   TouchCounter mTouchCounter;
+  /* Stores the current mouse position in screen coordinates.
+   */
+  ScreenPoint mCurrentMousePosition;
   /* For logging the APZC tree for debugging (enabled by the apz.printtree
    * pref). */
   gfx::TreeLog mApzcTreeLog;