Update from https://crrev.com/314320

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 20 matching lines @@
  public:
   struct CC_EXPORT Pair {
     Pair();
     Pair(PictureLayerImpl* active_layer, PictureLayerImpl* pending_layer);
     ~Pair();
 
     PictureLayerImpl* active;
     PictureLayerImpl* pending;
   };
 
-  static scoped_ptr<PictureLayerImpl> Create(LayerTreeImpl* tree_impl,
-                                             int id,
-                                             bool is_mask) {
-    return make_scoped_ptr(new PictureLayerImpl(tree_impl, id, is_mask));
+  static scoped_ptr<PictureLayerImpl> Create(
+      LayerTreeImpl* tree_impl,
+      int id,
+      bool is_mask,
+      scoped_refptr<SyncedScrollOffset> scroll_offset) {
+    return make_scoped_ptr(
+        new PictureLayerImpl(tree_impl, id, is_mask, scroll_offset));
   }
   ~PictureLayerImpl() override;
 
   bool is_mask() const { return is_mask_; }
 
   // LayerImpl overrides.
   const char* LayerTypeAsString() const override;
   scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
   void PushPropertiesTo(LayerImpl* layer) override;
   void AppendQuads(RenderPass* render_pass,
@@ skipping 35 matching lines @@
 
   bool CanHaveTilings() const;
 
   PictureLayerTilingSet* picture_layer_tiling_set() { return tilings_.get(); }
 
   // Functions used by tile manager.
   PictureLayerImpl* GetPendingOrActiveTwinLayer() const;
   bool IsOnActiveOrPendingTree() const;
   // Virtual for testing.
   virtual bool HasValidTilePriorities() const;
-  bool AllTilesRequiredForActivationAreReadyToDraw() const;
-  bool AllTilesRequiredForDrawAreReadyToDraw() const;
 
   // Used for benchmarking
   RasterSource* GetRasterSource() const { return raster_source_.get(); }
 
  protected:
   friend class LayerRasterTileIterator;
   using TileRequirementCheck = bool (PictureLayerTiling::*)(const Tile*) const;
 
-  PictureLayerImpl(LayerTreeImpl* tree_impl, int id, bool is_mask);
+  PictureLayerImpl(LayerTreeImpl* tree_impl,
+                   int id,
+                   bool is_mask,
+                   scoped_refptr<SyncedScrollOffset> scroll_offset);
   PictureLayerTiling* AddTiling(float contents_scale);
   void RemoveAllTilings();
   void AddTilingsForRasterScale();
   bool UpdateTilePriorities(const Occlusion& occlusion_in_content_space);
   virtual bool ShouldAdjustRasterScale() const;
   virtual void RecalculateRasterScales();
   void CleanUpTilingsOnActiveLayer(
-      std::vector<PictureLayerTiling*> used_tilings);
+      const std::vector<PictureLayerTiling*>& used_tilings);
   float MinimumContentsScale() const;
   float MaximumContentsScale() const;
   void ResetRasterScale();
   void UpdateViewportRectForTilePriorityInContentSpace();
   PictureLayerImpl* GetRecycledTwinLayer() const;
 
   void SanityCheckTilingState() const;
-  // Checks if all tiles required for a certain action (e.g. activation) are
-  // ready to draw.  is_tile_required_callback gets called on all candidate
-  // tiles and returns true if the tile is required for the action.
-  bool AllTilesRequiredAreReadyToDraw(
-      TileRequirementCheck is_tile_required_callback) const;
-
   bool ShouldAdjustRasterScaleDuringScaleAnimations() const;
 
   void GetDebugBorderProperties(SkColor* color, float* width) const override;
   void GetAllTilesForTracing(std::set<const Tile*>* tiles) const override;
   void AsValueInto(base::debug::TracedValue* dict) const override;
 
   virtual void UpdateIdealScales();
   float MaximumTilingContentsScale() const;
   scoped_ptr<PictureLayerTilingSet> CreatePictureLayerTilingSet();
 
@@ skipping 23 matching lines @@
 
   // Any draw properties derived from |transform|, |viewport|, and |clip|
   // parameters in LayerTreeHostImpl::SetExternalDrawConstraints are not valid
   // for prioritizing tiles during resourceless software draws. This is because
   // resourceless software draws can have wildly different transforms/viewports
   // from regular draws. Save a copy of the required draw properties of the last
   // frame that has a valid viewport for prioritizing tiles.
   gfx::Rect visible_rect_for_tile_priority_;
   gfx::Rect viewport_rect_for_tile_priority_in_content_space_;
 
+  // List of tilings that were used last time we appended quads. This can be
+  // used as an optimization not to remove tilings if they are still being
+  // drawn. Note that accessing this vector should only be done in the context
+  // of comparing pointers, since objects pointed to are not guaranteed to
+  // exist.
+  std::vector<PictureLayerTiling*> last_append_quads_tilings_;
+
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_IMPL_H_