Move scroll event handlers from layer to layer tree view.

cc/layers/layer.h

Index: cc/layers/layer.h
diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index 2b4272b78c0c2fc533d8da99b9fda45bdc7ef91f..82ba93b42f50f48ad12732d494a5963e417f644c 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -284,11 +284,6 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
     return !!main_thread_scrolling_reasons_;
   }
 
-  void SetHaveScrollEventHandlers(bool have_scroll_event_handlers);
-  bool have_scroll_event_handlers() const {
-    return have_scroll_event_handlers_;
-  }
-
   void SetNonFastScrollableRegion(const Region& non_fast_scrollable_region);
   const Region& non_fast_scrollable_region() const {
     return non_fast_scrollable_region_;
@@ -720,7 +715,6 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   gfx::Vector2dF offset_to_transform_parent_;
   uint32_t main_thread_scrolling_reasons_;
   bool should_flatten_transform_from_property_tree_ : 1;
-  bool have_scroll_event_handlers_ : 1;
   bool user_scrollable_horizontal_ : 1;
   bool user_scrollable_vertical_ : 1;
   bool is_root_for_isolated_group_ : 1;