Bug 962243 - Implement PINCH to TOUCHING transition in APZC. r=botond

--HG--
extra : commitid : FoHvf2KH9rd

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -1548,6 +1548,14 @@ nsEventStatus AsyncPanZoomController::OnScaleEnd(const PinchGestureInput& aEvent
     UpdateSharedCompositorFrameMetrics();
   }
 
+  // Non-negative focus point would indicate that one finger is still down
+  if (aEvent.mFocusPoint.x != -1 && aEvent.mFocusPoint.y != -1) {
+    mPanDirRestricted = false;
+    mX.StartTouch(aEvent.mFocusPoint.x, aEvent.mTime);
+    mY.StartTouch(aEvent.mFocusPoint.y, aEvent.mTime);
+    SetState(TOUCHING);
+  }
+
   return nsEventStatus_eConsumeNoDefault;
 }
 

gfx/layers/apz/src/GestureEventListener.cpp

@@ -101,6 +101,13 @@ nsEventStatus GestureEventListener::HandleInputEvent(const MultiTouchInput& aEve
     }
     break;
   case MultiTouchInput::MULTITOUCH_MOVE:
+    for (size_t i = 0; i < aEvent.mTouches.Length(); i++) {
+      for (size_t j = 0; j < mTouches.Length(); j++) {
+        if (aEvent.mTouches[i].mIdentifier == mTouches[j].mIdentifier) {
+          mTouches[j].mScreenPoint = aEvent.mTouches[i].mScreenPoint;
+        }
+      }
+    }
     rv = HandleInputTouchMove();
     break;
   case MultiTouchInput::MULTITOUCH_END:
@@ -375,10 +382,16 @@ nsEventStatus GestureEventListener::HandleInputTouchEnd()
   case GESTURE_PINCH:
     if (mTouches.Length() < 2) {
       SetState(GESTURE_NONE);
+      ScreenPoint point(-1, -1);
+      if (mTouches.Length() == 1) {
+        // As user still keeps one finger down the event's focus point should
+        // contain meaningful data.
+        point = mTouches[0].mScreenPoint;
+      }
       PinchGestureInput pinchEvent(PinchGestureInput::PINCHGESTURE_END,
                                    mLastTouchInput.mTime,
                                    mLastTouchInput.mTimeStamp,
-                                   ScreenPoint(),
+                                   point,
                                    1.0f,
                                    1.0f,
                                    mLastTouchInput.modifiers);

widget/InputData.h

@@ -455,6 +455,9 @@ public:
   // point is implementation-specific, but can for example be the midpoint
   // between the very first and very last touch. This is in device pixels and
   // are the coordinates on the screen of this midpoint.
+  // For PINCHGESTURE_END events, this instead will hold the coordinates of
+  // the remaining finger, if there is one. If there isn't one then it will
+  // store -1, -1.
   ScreenPoint mFocusPoint;
 
   // |mFocusPoint| transformed to the local coordinates of the APZC targeted