Chromium roll (https://codereview.chromium.org/976353002)

cc/resources/picture_layer_tiling_set.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_SET_H_
 #define CC_RESOURCES_PICTURE_LAYER_TILING_SET_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 37 matching lines @@
   const PictureLayerTilingClient* client() const { return client_; }
 
   void CleanUpTilings(float min_acceptable_high_res_scale,
                       float max_acceptable_high_res_scale,
                       const std::vector<PictureLayerTiling*>& needed_tilings,
                       bool should_have_low_res,
                       PictureLayerTilingSet* twin_set,
                       PictureLayerTilingSet* recycled_twin_set);
   void RemoveNonIdealTilings();
 
+  // This function can be called on both the active and pending tree.
+  // |pending_twin_set| represents the current pending twin. In situations where
+  // this is called on the active tree in two trees situations,
+  // |pending_twin_set| represents the tiling set from the pending twin layer.
+  // In situations where this is called on the sync tree (whether it's pending
+  // or active in cases of one tree), |pending_twin_set| should be nullptr.
   void UpdateTilingsToCurrentRasterSource(
       scoped_refptr<RasterSource> raster_source,
-      const PictureLayerTilingSet* twin_set,
+      const PictureLayerTilingSet* pending_twin_set,
       const Region& layer_invalidation,
       float minimum_contents_scale,
       float maximum_contents_scale);
 
   PictureLayerTiling* AddTiling(float contents_scale,
                                 scoped_refptr<RasterSource> raster_source);
   size_t num_tilings() const { return tilings_.size(); }
   int NumHighResTilings() const;
   PictureLayerTiling* tiling_at(size_t idx) { return tilings_[idx]; }
   const PictureLayerTiling* tiling_at(size_t idx) const {
@@ skipping 85 matching lines @@
 
   TilingRange GetTilingRange(TilingRangeType type) const;
 
  private:
   explicit PictureLayerTilingSet(
       PictureLayerTilingClient* client,
       size_t max_tiles_for_interest_area,
       float skewport_target_time_in_seconds,
       int skewport_extrapolation_limit_in_content_pixels);
 
+  void CopyTilingsFromPendingTwin(
+      const PictureLayerTilingSet* pending_twin_set,
+      const scoped_refptr<RasterSource>& raster_source);
+
   // Remove one tiling.
   void Remove(PictureLayerTiling* tiling);
 
   ScopedPtrVector<PictureLayerTiling> tilings_;
 
   const size_t max_tiles_for_interest_area_;
   const float skewport_target_time_in_seconds_;
   const int skewport_extrapolation_limit_in_content_pixels_;
   PictureLayerTilingClient* client_;
 
   friend class Iterator;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerTilingSet);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PICTURE_LAYER_TILING_SET_H_