Update from https://crrev.com/303153

cc/debug/rendering_stats.cc

Index: cc/debug/rendering_stats.cc
diff --git a/cc/debug/rendering_stats.cc b/cc/debug/rendering_stats.cc
index d0668da9b3a18505607cfa9b4cbe8a3311697276..558c882ec7c8f4a93f6227af9b9e4f509a815450 100644
--- a/cc/debug/rendering_stats.cc
+++ b/cc/debug/rendering_stats.cc
@@ -28,6 +28,10 @@ void RenderingStats::TimeDeltaList::Add(const TimeDeltaList& other) {
   values.insert(values.end(), other.values.begin(), other.values.end());
 }
 
+base::TimeDelta RenderingStats::TimeDeltaList::GetLastTimeDelta() const {
+  return values.empty() ? base::TimeDelta() : values.back();
+}
+
 RenderingStats::MainThreadRenderingStats::MainThreadRenderingStats()
     : painted_pixel_count(0), recorded_pixel_count(0) {
 }
@@ -56,7 +60,6 @@ void RenderingStats::MainThreadRenderingStats::Add(
 
 RenderingStats::ImplThreadRenderingStats::ImplThreadRenderingStats()
     : frame_count(0),
-      rasterized_pixel_count(0),
       visible_content_area(0),
       approximated_visible_content_area(0) {
 }
@@ -69,8 +72,6 @@ RenderingStats::ImplThreadRenderingStats::AsTraceableData() const {
   scoped_refptr<base::debug::TracedValue> record_data =
       new base::debug::TracedValue();
   record_data->SetInteger("frame_count", frame_count);
-  record_data->SetDouble("rasterize_time", rasterize_time.InSecondsF());
-  record_data->SetInteger("rasterized_pixel_count", rasterized_pixel_count);
   record_data->SetInteger("visible_content_area", visible_content_area);
   record_data->SetInteger("approximated_visible_content_area",
                           approximated_visible_content_area);
@@ -104,9 +105,6 @@ RenderingStats::ImplThreadRenderingStats::AsTraceableData() const {
 void RenderingStats::ImplThreadRenderingStats::Add(
     const ImplThreadRenderingStats& other) {
   frame_count += other.frame_count;
-  rasterize_time += other.rasterize_time;
-  analysis_time += other.analysis_time;
-  rasterized_pixel_count += other.rasterized_pixel_count;
   visible_content_area += other.visible_content_area;
   approximated_visible_content_area += other.approximated_visible_content_area;