Adding a metric to track only the checkerboarding.

BUG=466867

Review URL: https://codereview.chromium.org/1010323002

Cr-Commit-Position: refs/heads/master@{#322396}

cc/debug/rendering_stats.cc

@@ -37,7 +37,8 @@ base::TimeDelta RenderingStats::TimeDeltaList::GetLastTimeDelta() const {
 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() {
@@ -51,6 +52,8 @@ RenderingStats::AsTraceableData() const {
   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",
@@ -74,6 +77,8 @@ 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);

cc/debug/rendering_stats.h

@@ -44,6 +44,7 @@ struct CC_EXPORT RenderingStats {
   int64 frame_count;
   int64 visible_content_area;
   int64 approximated_visible_content_area;
+  int64 checkerboarded_visible_content_area;
 
   TimeDeltaList draw_duration;
   TimeDeltaList draw_duration_estimate;

cc/debug/rendering_stats_instrumentation.cc

@@ -81,6 +81,15 @@ void RenderingStatsInstrumentation::AddApproximatedVisibleContentArea(
   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) {

cc/debug/rendering_stats_instrumentation.h

@@ -43,6 +43,7 @@ class CC_EXPORT RenderingStatsInstrumentation {
   void IncrementFrameCount(int64 count);
   void AddVisibleContentArea(int64 area);
   void AddApproximatedVisibleContentArea(int64 area);
+  void AddCheckerboardedVisibleContentArea(int64 area);
   void AddDrawDuration(base::TimeDelta draw_duration,
                        base::TimeDelta draw_duration_estimate);
   void AddBeginMainFrameToCommitDuration(

cc/layers/append_quads_data.h

@@ -15,7 +15,8 @@ struct AppendQuadsData {
       : num_incomplete_tiles(0),
         num_missing_tiles(0),
         visible_content_area(0),
-        approximated_visible_content_area(0) {}
+        approximated_visible_content_area(0),
+        checkerboarded_visible_content_area(0) {}
 
   // Set by the layer appending quads.
   int64 num_incomplete_tiles;
@@ -25,6 +26,8 @@ struct AppendQuadsData {
   int64 visible_content_area;
   // Set by the layer appending quads.
   int64 approximated_visible_content_area;
+  // Set by the layer appending quads.
+  int64 checkerboarded_visible_content_area;
 };
 
 }  // namespace cc

cc/layers/picture_layer_impl.cc

@@ -351,6 +351,8 @@ void PictureLayerImpl::AppendQuads(RenderPass* render_pass,
       }
       append_quads_data->approximated_visible_content_area +=
           visible_geometry_rect.width() * visible_geometry_rect.height();
+      append_quads_data->checkerboarded_visible_content_area +=
+          visible_geometry_rect.width() * visible_geometry_rect.height();
       continue;
     }
 

cc/trees/layer_tree_host_impl.cc

@@ -844,6 +844,8 @@ DrawResult LayerTreeHostImpl::CalculateRenderPasses(
         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;