Adding a metric to track only the checkerboarding.

cc/debug/rendering_stats_instrumentation.cc

 // 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.
 
 #include "cc/debug/rendering_stats_instrumentation.h"
 
 namespace cc {
 
 // static
 scoped_ptr<RenderingStatsInstrumentation>
@@ skipping 63 matching lines @@
 
 void RenderingStatsInstrumentation::AddApproximatedVisibleContentArea(
     int64 area) {
   if (!record_rendering_stats_)
     return;
 
   base::AutoLock scoped_lock(lock_);
   impl_thread_rendering_stats_.approximated_visible_content_area += area;
 }
 
+void RenderingStatsInstrumentation::AddCheckerboardedVisibleContentArea(
+    int64 area) {
+  if (!record_rendering_stats_)
+    return;
+
+  base::AutoLock scoped_lock(lock_);
+  impl_thread_rendering_stats_.checkerboarded_visible_content_area += area;
+}
+
 void RenderingStatsInstrumentation::AddDrawDuration(
     base::TimeDelta draw_duration,
     base::TimeDelta draw_duration_estimate) {
   if (!record_rendering_stats_)
     return;
 
   base::AutoLock scoped_lock(lock_);
   impl_thread_rendering_stats_.draw_duration.Append(draw_duration);
   impl_thread_rendering_stats_.draw_duration_estimate.Append(
       draw_duration_estimate);
@@ skipping 19 matching lines @@
     return;
 
   base::AutoLock scoped_lock(lock_);
   impl_thread_rendering_stats_.commit_to_activate_duration.Append(
       commit_to_activate_duration);
   impl_thread_rendering_stats_.commit_to_activate_duration_estimate.Append(
       commit_to_activate_duration_estimate);
 }
 
 }  // namespace cc