cc: Report only on active tiles in tracing.

cc/resources/picture_layer_tiling.cc

 // 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.
 
 #include "cc/resources/picture_layer_tiling.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
+#include <set>
 
 #include "base/debug/trace_event.h"
 #include "base/debug/trace_event_argument.h"
 #include "cc/base/math_util.h"
 #include "cc/resources/tile.h"
 #include "cc/resources/tile_priority.h"
 #include "cc/trees/occlusion_tracker.h"
 #include "ui/gfx/point_conversions.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/safe_integer_conversions.h"
@@ skipping 641 matching lines @@
     // Tile holds a ref onto a picture pile. If the tile never gets invalidated
     // and recreated, then that picture pile ref could exist indefinitely.  To
     // prevent this, ask the client to update the pile to its own ref.  This
     // will cause PicturePileImpls and their clones to get deleted once the
     // corresponding PictureLayerImpl and any in flight raster jobs go out of
     // scope.
     it->second->set_picture_pile(active_pile);
   }
 }
 
+void PictureLayerTiling::AllTilesForTracingInto(
+    std::set<const Tile*>* tiles) const {
+  for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it)
+    tiles->insert(it->second.get());
+}
+
 void PictureLayerTiling::AsValueInto(base::debug::TracedValue* state) const {
   state->SetInteger("num_tiles", tiles_.size());
   state->SetDouble("content_scale", contents_scale_);
   state->BeginDictionary("tiling_size");
   MathUtil::AddToTracedValue(tiling_size(), state);
   state->EndDictionary();
 }
 
 size_t PictureLayerTiling::GPUMemoryUsageInBytes() const {
   size_t amount = 0;
@@ skipping 404 matching lines @@
   DCHECK(*this);
   do {
     ++current_eviction_tiles_index_;
   } while (current_eviction_tiles_index_ != eviction_tiles_->size() &&
            !(*eviction_tiles_)[current_eviction_tiles_index_]->HasResources());
 
   return *this;
 }
 
 }  // namespace cc