Adding a metric to track only the checkerboarding.

cc/debug/rendering_stats.cc

 // Copyright 2012 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.
 
 #include "cc/debug/rendering_stats.h"
 
 namespace cc {
 
 RenderingStats::TimeDeltaList::TimeDeltaList() {
 }
@@ skipping 19 matching lines @@
   values.insert(values.end(), other.values.begin(), other.values.end());
 }
 
 base::TimeDelta RenderingStats::TimeDeltaList::GetLastTimeDelta() const {
   return values.empty() ? base::TimeDelta() : values.back();
 }
 
 RenderingStats::RenderingStats()
     : frame_count(0),
       visible_content_area(0),
-      approximated_visible_content_area(0) {
+      approximated_visible_content_area(0),
+      checkerboarded_visible_content_area(0) {
 }
 
 RenderingStats::~RenderingStats() {
 }
 
 scoped_refptr<base::trace_event::ConvertableToTraceFormat>
 RenderingStats::AsTraceableData() const {
   scoped_refptr<base::trace_event::TracedValue> record_data =
       new base::trace_event::TracedValue();
   record_data->SetInteger("frame_count", frame_count);
   record_data->SetInteger("visible_content_area", visible_content_area);
   record_data->SetInteger("approximated_visible_content_area",
                           approximated_visible_content_area);
+  record_data->SetInteger("checkerboarded_visible_content_area",
+                          checkerboarded_visible_content_area);
   draw_duration.AddToTracedValue("draw_duration_ms", record_data.get());
 
   draw_duration_estimate.AddToTracedValue("draw_duration_estimate_ms",
                                           record_data.get());
 
   begin_main_frame_to_commit_duration.AddToTracedValue(
       "begin_main_frame_to_commit_duration_ms", record_data.get());
 
   begin_main_frame_to_commit_duration_estimate.AddToTracedValue(
       "begin_main_frame_to_commit_duration_estimate_ms", record_data.get());
 
   commit_to_activate_duration.AddToTracedValue("commit_to_activate_duration_ms",
                                                record_data.get());
 
   commit_to_activate_duration_estimate.AddToTracedValue(
       "commit_to_activate_duration_estimate_ms", record_data.get());
   return record_data;
 }
 
 void RenderingStats::Add(const RenderingStats& other) {
   frame_count += other.frame_count;
   visible_content_area += other.visible_content_area;
   approximated_visible_content_area += other.approximated_visible_content_area;
+  checkerboarded_visible_content_area +=
+      other.checkerboarded_visible_content_area;
 
   draw_duration.Add(other.draw_duration);
   draw_duration_estimate.Add(other.draw_duration_estimate);
   begin_main_frame_to_commit_duration.Add(
       other.begin_main_frame_to_commit_duration);
   begin_main_frame_to_commit_duration_estimate.Add(
       other.begin_main_frame_to_commit_duration_estimate);
   commit_to_activate_duration.Add(other.commit_to_activate_duration);
   commit_to_activate_duration_estimate.Add(
       other.commit_to_activate_duration_estimate);
 }
 
 }  // namespace cc