cc: Report only on active tiles in tracing.

cc/resources/picture_layer_tiling.h

 // Copyright 2012 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_RESOURCES_PICTURE_LAYER_TILING_H_
 #define CC_RESOURCES_PICTURE_LAYER_TILING_H_
 
+#include <set>
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/region.h"
 #include "cc/base/tiling_data.h"
 #include "cc/resources/tile.h"
@@ skipping 234 matching lines @@
   // tiling is becoming recycled. This may include some tiles which are
   // not in the the pending tiling (due to invalidations). This must
   // be called before DidBecomeActive, as it resets the active priority
   // while DidBecomeActive promotes pending priority on a similar set of tiles.
   void DidBecomeRecycled();
 
   bool NeedsUpdateForFrameAtTime(double frame_time_in_seconds) {
     return frame_time_in_seconds != last_impl_frame_time_in_seconds_;
   }
 
+  void AllTilesForTracingInto(std::set<const Tile*>* tiles) const;
   void AsValueInto(base::debug::TracedValue* array) const;
   size_t GPUMemoryUsageInBytes() const;
 
   struct RectExpansionCache {
     RectExpansionCache();
 
     gfx::Rect previous_start;
     gfx::Rect previous_bounds;
     gfx::Rect previous_result;
     int64 previous_target;
@@ skipping 82 matching lines @@
 
  private:
   DISALLOW_ASSIGN(PictureLayerTiling);
 
   RectExpansionCache expansion_cache_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_H_