Add telemetry to track the time an event spent waiting for the main thread.

content/common/browser_rendering_stats.h

 // Copyright 2013 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.
 
 #ifndef CONTENT_COMMON_BROWSER_RENDERING_STATS_H_
 #define CONTENT_COMMON_BROWSER_RENDERING_STATS_H_
 
 #include "base/time/time.h"
 #include "cc/debug/rendering_stats.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 struct CONTENT_EXPORT BrowserRenderingStats {
   BrowserRenderingStats();
   ~BrowserRenderingStats();
 
   uint32 input_event_count;
   base::TimeDelta total_input_latency;
 
   uint32 touch_ui_count;
   base::TimeDelta total_touch_ui_latency;
   uint32 touch_acked_count;
   base::TimeDelta total_touch_acked_latency;
 
   uint32 scroll_update_count;
   base::TimeDelta total_scroll_update_latency;
+
+  uint32 impl_to_main_touch_event_count;
+  base::TimeDelta total_impl_to_main_touch_event_latency;
+  uint32 impl_to_main_gesture_scroll_event_count;
+  base::TimeDelta total_impl_to_main_gesture_scroll_event_latency;
   // Note: when adding new members, please remember to update enumerateFields
   // in browser_rendering_stats.cc.
 
   // Outputs the fields in this structure to the provided enumerator.
   void EnumerateFields(cc::RenderingStats::Enumerator* enumerator) const;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_BROWSER_RENDERING_STATS_H_