Revert of Early terminate flings when scrolling impossible

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index dc20aaf95a675c1b98ea7a2cee84ca20a91f9770..10477dc2af297d281ab1eefeac22c6a87fe16893 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -123,6 +123,8 @@
   virtual void OnRootLayerDelegatedScrollOffsetChanged() OVERRIDE;
   virtual void ScrollEnd() OVERRIDE;
   virtual InputHandler::ScrollStatus FlingScrollBegin() OVERRIDE;
+  virtual void NotifyCurrentFlingVelocity(
+      const gfx::Vector2dF& velocity) OVERRIDE;
   virtual void MouseMoveAt(const gfx::Point& viewport_point) OVERRIDE;
   virtual void PinchGestureBegin() OVERRIDE;
   virtual void PinchGestureUpdate(float magnify_delta,
@@ -378,6 +380,9 @@
   gfx::Vector2dF accumulated_root_overscroll() const {
     return accumulated_root_overscroll_;
   }
+  gfx::Vector2dF current_fling_velocity() const {
+    return current_fling_velocity_;
+  }
 
   bool pinch_gesture_active() const { return pinch_gesture_active_; }
 
@@ -564,6 +569,7 @@
   ManagedMemoryPolicy cached_managed_memory_policy_;
 
   gfx::Vector2dF accumulated_root_overscroll_;
+  gfx::Vector2dF current_fling_velocity_;
 
   bool pinch_gesture_active_;
   bool pinch_gesture_end_should_clear_scrolling_layer_;