cc: Clean up tilings in UpdateTiles as well as in AppendQuads.

cc/test/fake_picture_layer_impl.h

 // 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_TEST_FAKE_PICTURE_LAYER_IMPL_H_
 #define CC_TEST_FAKE_PICTURE_LAYER_IMPL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/layers/picture_layer_impl.h"
 
@@ skipping 103 matching lines @@
   void set_fixed_tile_size(const gfx::Size& size) { fixed_tile_size_ = size; }
 
   void CreateAllTiles();
   void SetAllTilesVisible();
   void SetAllTilesReady();
   void SetAllTilesReadyInTiling(PictureLayerTiling* tiling);
   void SetTileReady(Tile* tile);
   void ResetAllTilesPriorities();
   PictureLayerTilingSet* GetTilings() { return tilings_.get(); }
 
+  // Add the given tiling as a "used" tiling during AppendQuads. This ensures
+  // that future calls to UpdateTiles don't delete the tiling.
+  void AddUsedTiling(PictureLayerTiling* tiling) {
+    last_append_quads_tilings_.push_back(tiling);
+  }
+
   size_t release_resources_count() const { return release_resources_count_; }
   void reset_release_resources_count() { release_resources_count_ = 0; }
 
   void ReleaseResources() override;
 
   bool only_used_low_res_last_append_quads() const {
     return only_used_low_res_last_append_quads_;
   }
 
  protected:
@@ skipping 14 matching lines @@
   size_t append_quads_count_;
   size_t did_become_active_call_count_;
   bool has_valid_tile_priorities_;
   bool use_set_valid_tile_priorities_flag_;
   size_t release_resources_count_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_PICTURE_LAYER_IMPL_H_