Bug 1401450 - Fix incorrect guid and input block id when sending coalesced mouse move event. r=smaug.

dom/ipc/TabChild.cpp

@@ -1599,8 +1599,8 @@ TabChild::MaybeDispatchCoalescedMouseMoveEvents()
   // Dispatch the coalesced mousemove event. Using RecvRealMouseButtonEvent to
   // bypass the coalesce handling in RecvRealMouseMoveEvent.
   RecvRealMouseButtonEvent(*event,
-                           mCoalescedWheelData.GetScrollableLayerGuid(),
-                           mCoalescedWheelData.GetInputBlockId());
+                           mCoalescedMouseData.GetScrollableLayerGuid(),
+                           mCoalescedMouseData.GetInputBlockId());
   if (mCoalescedMouseEventFlusher) {
     mCoalescedMouseData.Reset();
     mCoalescedMouseEventFlusher->RemoveObserver();