Scroll with Layers in views::ScrollView

cc/input/input_handler.h

Index: cc/input/input_handler.h
diff --git a/cc/input/input_handler.h b/cc/input/input_handler.h
index 11a33105b1ef87efc0eaedb2827dffa97b8eb73d..bd11a620bbff2038ab1a8e74a38abf5f56c39eee 100644
--- a/cc/input/input_handler.h
+++ b/cc/input/input_handler.h
@@ -198,6 +198,12 @@ class CC_EXPORT InputHandler {
 
   virtual ScrollElasticityHelper* CreateScrollElasticityHelper() = 0;
 
+  // Called by the single-threaded UI Compositor to get or set the scroll offset
+  // on the impl side. Retruns false if |layer_id| isn't in the active tree.
+  virtual bool GetScrollOffsetForLayer(int layer_id,
+                                       gfx::ScrollOffset* offset) = 0;
+  virtual bool ScrollLayerTo(int layer_id, const gfx::ScrollOffset& offset) = 0;
+
  protected:
   InputHandler() {}
   virtual ~InputHandler() {}