Adding a metric to track only the checkerboarding.

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 
@@ skipping 823 matching lines @@
         }
       }
 
       ++layers_drawn;
     }
 
     rendering_stats_instrumentation_->AddVisibleContentArea(
         append_quads_data.visible_content_area);
     rendering_stats_instrumentation_->AddApproximatedVisibleContentArea(
         append_quads_data.approximated_visible_content_area);
+    rendering_stats_instrumentation_->AddCheckerboardedVisibleContentArea(
+        append_quads_data.checkerboarded_visible_content_area);
 
     num_missing_tiles += append_quads_data.num_missing_tiles;
     num_incomplete_tiles += append_quads_data.num_incomplete_tiles;
 
     if (append_quads_data.num_missing_tiles) {
       bool layer_has_animating_transform =
           it->screen_space_transform_is_animating() ||
           it->draw_transform_is_animating();
       if (layer_has_animating_transform)
         have_missing_animated_tiles = true;
@@ skipping 2610 matching lines @@
   new_target.SetToMin(layer_impl->MaxScrollOffset());
 
   curve->UpdateTarget(
       animation->TrimTimeToCurrentIteration(CurrentBeginFrameArgs().frame_time)
           .InSecondsF(),
       new_target);
 
   return true;
 }
 }  // namespace cc