cc: Impl thread scroll on ScrollNode instead of LayerImpl

cc/trees/property_tree.h

 // Copyright 2014 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_TREES_PROPERTY_TREE_H_
 #define CC_TREES_PROPERTY_TREE_H_
 
 #include <stddef.h>
 
 #include <unordered_map>
@@ skipping 12 matching lines @@
 class EffectNodeData;
 class PropertyTree;
 class PropertyTrees;
 class ScrollNodeData;
 class TranformNodeData;
 class TransformTreeData;
 class TreeNode;
 }
 
 class LayerTreeImpl;
+class ScrollState;
 struct ScrollAndScaleSet;
 
 // ------------------------------*IMPORTANT*---------------------------------
 // Each class declared here has a corresponding proto defined in
 // cc/proto/property_tree.proto. When making any changes to a class structure
 // including addition/deletion/updation of a field, please also make the
 // change to its proto and the ToProtobuf and FromProtobuf methods for that
 // class.
 
 typedef SyncedProperty<AdditionGroup<gfx::ScrollOffset>> SyncedScrollOffset;
@@ skipping 546 matching lines @@
     synced_scroll_offset(layer_id)->set_clobber_active_value();
   }
   bool UpdateScrollOffsetBaseForTesting(int layer_id,
                                         const gfx::ScrollOffset& offset);
   bool SetScrollOffsetDeltaForTesting(int layer_id,
                                       const gfx::Vector2dF& delta);
   const gfx::ScrollOffset GetScrollOffsetBaseForTesting(int layer_id) const;
   const gfx::ScrollOffset GetScrollOffsetDeltaForTesting(int layer_id) const;
   void CollectScrollDeltasForTesting();
 
+  void DistributeScroll(ScrollNode* scroll_node, ScrollState* scroll_state);
+  gfx::Vector2dF ScrollBy(ScrollNode* scroll_node,
+                          const gfx::Vector2dF& scroll,
+                          LayerTreeImpl* layer_tree_impl);
+
  private:
   int currently_scrolling_node_id_;
   ScrollOffsetMap layer_id_to_scroll_offset_map_;
 
   SyncedScrollOffset* synced_scroll_offset(int layer_id);
   const SyncedScrollOffset* synced_scroll_offset(int layer_id) const;
   gfx::ScrollOffset PullDeltaForMainThread(SyncedScrollOffset* scroll_offset);
   void UpdateScrollOffsetMapEntry(int key,
                                   ScrollOffsetMap* new_scroll_offset_map,
                                   LayerTreeImpl* layer_tree_impl);
+  gfx::ScrollOffset ClampScrollOffsetToLimits(gfx::ScrollOffset offset,
+                                              ScrollNode* scroll_node) const;
 };
 
 class CC_EXPORT PropertyTrees final {
  public:
   PropertyTrees();
   ~PropertyTrees();
 
   bool operator==(const PropertyTrees& other) const;
   PropertyTrees& operator=(const PropertyTrees& from);
 
@@ skipping 42 matching lines @@
 
  private:
   gfx::Vector2dF inner_viewport_container_bounds_delta_;
   gfx::Vector2dF outer_viewport_container_bounds_delta_;
   gfx::Vector2dF inner_viewport_scroll_bounds_delta_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_