Add duration estimation data to RenderingStats.

cc/debug/rendering_stats.h

Index: cc/debug/rendering_stats.h
diff --git a/cc/debug/rendering_stats.h b/cc/debug/rendering_stats.h
index bd3b7c7244282fdd6888ae31fc67d0ea41de8758..f0ee8e106a14a16534ef245e5f4208a4625c3306 100644
--- a/cc/debug/rendering_stats.h
+++ b/cc/debug/rendering_stats.h
@@ -5,6 +5,8 @@
 #ifndef CC_DEBUG_RENDERING_STATS_H_
 #define CC_DEBUG_RENDERING_STATS_H_
 
+#include <list>
+
 #include "base/basictypes.h"
 #include "base/time/time.h"
 #include "cc/base/cc_export.h"
@@ -27,6 +29,17 @@ struct CC_EXPORT MainThreadRenderingStats {
   void Add(const MainThreadRenderingStats& other);
 };
 
+// Stores a sequence of TimeDelta objects.
+class CC_EXPORT ImplThreadRenderingStatsAccumulated {

[brianderson, 2014/07/07 20:01:42]

What's the plan for how to process/display/use the history of values?

[Dominik Grewe, 2014/07/07 20:42:32]

Potentially several things:

1) Add a metric to Telemetry to measure the error of estimates (seems to be
quite noisy though, so not sure how useful this will be).

2) Make data visible in trace viewer similar to input latency diagrams.

3) For tuning of the estimators.

[brianderson, 2014/07/07 21:43:14]

How would we get the list of timestamps out? I know there are mechanisms to get
per-frame stats out, but they don't appear to be implemented using rendering
stats. Should this be using a different mechanism instead?
How would it hook up to the trace viewer? Should we have trace events in the
ProxyTimingHistory class instead?

+ public:
+  void Append(base::TimeDelta value);
+  scoped_ptr<base::Value> AsValueInMilliseconds() const;
+  void Add(const ImplThreadRenderingStatsAccumulated& other);
+
+ private:
+  std::list<base::TimeDelta> values;
+};
+
 struct CC_EXPORT ImplThreadRenderingStats {
   // Note: when adding new members, please remember to update EnumerateFields
   // and Add in rendering_stats.cc.
@@ -38,6 +51,14 @@ struct CC_EXPORT ImplThreadRenderingStats {
   int64 visible_content_area;
   int64 approximated_visible_content_area;
 
+  ImplThreadRenderingStatsAccumulated draw_duration;
+  ImplThreadRenderingStatsAccumulated draw_duration_estimate;
+  ImplThreadRenderingStatsAccumulated begin_main_frame_to_commit_duration;
+  ImplThreadRenderingStatsAccumulated
+      begin_main_frame_to_commit_duration_estimate;
+  ImplThreadRenderingStatsAccumulated commit_to_activate_duration;
+  ImplThreadRenderingStatsAccumulated commit_to_activate_duration_estimate;
+
   ImplThreadRenderingStats();
   scoped_refptr<base::debug::ConvertableToTraceFormat> AsTraceableData() const;
   void Add(const ImplThreadRenderingStats& other);