Avoid heap allocation with uncoalesced touch events

content/browser/renderer_host/input/touch_event_queue.h

Index: content/browser/renderer_host/input/touch_event_queue.h
diff --git a/content/browser/renderer_host/input/touch_event_queue.h b/content/browser/renderer_host/input/touch_event_queue.h
index 0e240730566dfabcdc401deaf70e72aaf7d66fb5..a45e60f272e5a72bad6f0081bd7dc86250416650 100644
--- a/content/browser/renderer_host/input/touch_event_queue.h
+++ b/content/browser/renderer_host/input/touch_event_queue.h
@@ -160,9 +160,11 @@ class CONTENT_EXPORT TouchEventQueue {
   void PopTouchEventToClient(InputEventAckState ack_result,
                              const ui::LatencyInfo& renderer_latency_info);
 
-  // Ack all coalesced events in |acked_event| to the client with |ack_result|.
+  // Ack all coalesced events in |acked_event| to the client with |ack_result|,
+  // updating the acked events with |optional_latency_info| if it exists.
   void AckTouchEventToClient(InputEventAckState ack_result,
-                             scoped_ptr<CoalescedWebTouchEvent> acked_event);
+                             scoped_ptr<CoalescedWebTouchEvent> acked_event,
+                             const ui::LatencyInfo* optional_latency_info);
 
   // Safely pop the head of the queue.
   scoped_ptr<CoalescedWebTouchEvent> PopTouchEvent();