Bug 1304729 - Ensure we schedule a composite if we change the scroll position during a pinch gesture with no zoom change. r=botond

MozReview-Commit-ID: AF2aoJZ1ssG

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -1394,8 +1394,6 @@ nsEventStatus AsyncPanZoomController::OnScale(const PinchGestureInput& aEvent) {
         ScrollBy(neededDisplacement);
       }
 
-      ScheduleComposite();
-
       // We don't want to redraw on every scale, so throttle it.
       if (!mPinchPaintTimerSet) {
         const int delay = gfxPrefs::APZScaleRepaintDelay();
@@ -1413,6 +1411,10 @@ nsEventStatus AsyncPanZoomController::OnScale(const PinchGestureInput& aEvent) {
       UpdateSharedCompositorFrameMetrics();
     }
 
+    // We did a ScrollBy call above even if we didn't do a scale, so we
+    // should composite for that.
+    ScheduleComposite();
+
     mLastZoomFocus = focusPoint;
   }