cc:: Add RenderingStatsInstrumentation to manage collection of RenderingStats

cc/rendering_stats_recorder.h

Index: cc/rendering_stats_recorder.h
diff --git a/cc/rendering_stats_recorder.h b/cc/rendering_stats_recorder.h
new file mode 100644
index 0000000000000000000000000000000000000000..a10d9e919baae0a55e2f24100e7468e0053537c3
--- /dev/null
+++ b/cc/rendering_stats_recorder.h
@@ -0,0 +1,68 @@
+// 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.
+
+#ifndef CC_RENDERING_STATS_RECORDER_H_
+#define CC_RENDERING_STATS_RECORDER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/synchronization/lock.h"
+#include "cc/rendering_stats.h"
+
+namespace cc {
+
+// RenderingStatsRecorder is shared among threads and manages conditional
+// recording of rendering stats into a private RenderingStats instance.
+class CC_EXPORT RenderingStatsRecorder {

[egraether, 2013/03/12 19:31:42]

Nat suggested to name the class RenderingStatsInstrumentation to follow the
naming of the newly added devtools_instrumentation. I prefer recorder, but I'm
fine to change it (I only want to change it once though).

[danakj, 2013/03/13 17:25:41]

I'm okay with either, so I think go with Nat's preference.

[egraether, 2013/03/14 18:58:07]

Done.

+ public:
+  static scoped_ptr<RenderingStatsRecorder> create();
+
+  RenderingStats GetRenderingStats();
+
+  // Read and write access to the record_rendering_stats_ flag is not locked to
+  // improve performance. The flag is commonly turned off and hardly changes
+  // it's value during runtime.
+  bool record_rendering_stats() const;
+  void set_record_rendering_stats(bool record_rendering_stats);
+
+  base::TimeTicks StartRecording() const;
+  base::TimeDelta EndRecording(base::TimeTicks start_time) const;
+
+  // TODO: Remove after switching Layer::update() to use this class.
+  // Used in LayerTreeHost::paintLayerContents().
+  void AddStats(const RenderingStats& other);
+
+  void IncrementAnimationFrameCount();
+  void SetScreenAndDroppedFrameCount(int64 screen_total, int64 dropped_total);
+
+  void AddCommit(base::TimeDelta duration);
+  void AddPaint(base::TimeDelta duration, int64 pixels);
+  void AddRaster(base::TimeDelta duration,
+                 int64 pixels,
+                 bool is_in_pending_tree_now_bin);
+
+  void IncrementImplThreadScrolls();
+  void IncrementMainThreadScrolls();
+
+  void AddLayersDrawn(int64 amount);
+  void AddMissingTiles(int64 amount);
+
+  void AddDeferredImageDecode(base::TimeDelta duration);
+  void AddImageGathering(base::TimeDelta duration);
+
+  void IncrementDeferredImageCacheHitCount();
+
+ private:
+  RenderingStatsRecorder();
+
+  RenderingStats rendering_stats_;
+  bool record_rendering_stats_;
+
+  base::Lock lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(RenderingStatsRecorder);
+};
+
+}  // namespace cc
+
+#endif  // CC_RENDERING_STATS_RECORDER_H_