Make sure resent events that don't match ids are not coalesced.

ui/events/blink/blink_event_util.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // MSVC++ requires this to be set before any other includes to get M_PI.
 #define _USE_MATH_DEFINES
 
 #include "ui/events/blink/blink_event_util.h"
 
 #include <stddef.h>
@@ skipping 243 matching lines @@
   event->movementX += x;
   event->movementY += y;
 }
 
 bool CanCoalesce(const WebMouseWheelEvent& event_to_coalesce,
                  const WebMouseWheelEvent& event) {
   return event.modifiers() == event_to_coalesce.modifiers() &&
          event.scrollByPage == event_to_coalesce.scrollByPage &&
          event.phase == event_to_coalesce.phase &&
          event.momentumPhase == event_to_coalesce.momentumPhase &&
+         event.resendingPluginId == event_to_coalesce.resendingPluginId &&
          event.hasPreciseScrollingDeltas ==
              event_to_coalesce.hasPreciseScrollingDeltas;
 }
 
 void Coalesce(const WebMouseWheelEvent& event_to_coalesce,
               WebMouseWheelEvent* event) {
   DCHECK(CanCoalesce(event_to_coalesce, *event));
   float unaccelerated_x =
       GetUnacceleratedDelta(event->deltaX, event->accelerationRatioX) +
       GetUnacceleratedDelta(event_to_coalesce.deltaX,
@@ skipping 66 matching lines @@
     }
   }
   event->movedBeyondSlopRegion |= old_event.movedBeyondSlopRegion;
   event->dispatchType = MergeDispatchTypes(old_event.dispatchType,
                                            event_to_coalesce.dispatchType);
 }
 
 bool CanCoalesce(const WebGestureEvent& event_to_coalesce,
                  const WebGestureEvent& event) {
   if (event.type() != event_to_coalesce.type() ||
+      event.resendingPluginId != event_to_coalesce.resendingPluginId ||
       event.sourceDevice != event_to_coalesce.sourceDevice ||
       event.modifiers() != event_to_coalesce.modifiers())
     return false;
 
   if (event.type() == WebInputEvent::GestureScrollUpdate)
     return true;
 
   // GesturePinchUpdate scales can be combined only if they share a focal point,
   // e.g., with double-tap drag zoom.
   if (event.type() == WebInputEvent::GesturePinchUpdate &&
@@ skipping 618 matching lines @@
   switch (type) {
     case blink::WebGestureEvent::GestureScrollUpdate:
     case blink::WebGestureEvent::GesturePinchUpdate:
       return true;
     default:
       return false;
   }
 }
 
 }  // namespace ui