cc: Rework how PLI cleans tilings up.

cc/layers/picture_layer_impl.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_LAYERS_PICTURE_LAYER_IMPL_H_
 #define CC_LAYERS_PICTURE_LAYER_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 140 matching lines @@
   virtual bool HasValidTilePriorities() const;
   bool AllTilesRequiredForActivationAreReadyToDraw() const;
   bool AllTilesRequiredForDrawAreReadyToDraw() const;
 
  protected:
   friend class LayerRasterTileIterator;
   using TileRequirementCheck = bool (PictureLayerTiling::*)(const Tile*) const;
 
   PictureLayerImpl(LayerTreeImpl* tree_impl, int id);
   PictureLayerTiling* AddTiling(float contents_scale);
-  void RemoveTiling(float contents_scale);
   void RemoveAllTilings();
   void SyncFromActiveLayer(const PictureLayerImpl* other);
   void AddTilingsForRasterScale();
   void UpdateTilePriorities(const Occlusion& occlusion_in_content_space);
   virtual bool ShouldAdjustRasterScale() const;
   virtual void RecalculateRasterScales();
   void CleanUpTilingsOnActiveLayer(
       std::vector<PictureLayerTiling*> used_tilings);
   float MinimumContentsScale() const;
   void ResetRasterScale();
@@ skipping 59 matching lines @@
   // frame that has a valid viewport for prioritizing tiles.
   gfx::Rect visible_rect_for_tile_priority_;
 
   friend class PictureLayer;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_IMPL_H_