Add initial CC support for scroll-blocks-on

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 020862726a3c65c859dc835e046dbf4800290e1d..d899a85156e4b63160f3d946b6a65398b2a3aff8 100644
--- a/cc/input/input_handler.h
+++ b/cc/input/input_handler.h
@@ -143,7 +143,10 @@ class CC_EXPORT InputHandler {
                                            ScrollInputType type) = 0;
 
   virtual bool HaveWheelEventHandlersAt(const gfx::Point& viewport_point) = 0;
-  virtual bool HaveTouchEventHandlersAt(const gfx::Point& viewport_point) = 0;
+
+  // Whether the page should be given the opportunity to suppress scrolling by
+  // consuming touch events that started at |viewport_point|.
+  virtual bool DoTouchEventsBlockScrollAt(const gfx::Point& viewport_point) = 0;
 
   // Calling CreateLatencyInfoSwapPromiseMonitor() to get a scoped
   // LatencyInfoSwapPromiseMonitor. During the life time of the