currentlyscrollinglayer cleared in scrollAnimatedBegin.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 2ec8f709dc2add212eb5f63ffc57fd2fa8bf4ee9..53f3dadcb41549257b77eb201a68f3292e0df76a 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -2788,7 +2788,7 @@ InputHandler::ScrollStatus LayerTreeHostImpl::ScrollAnimatedBegin(
   ScrollStateData scroll_state_data;
   scroll_state_data.position_x = viewport_point.x();
   scroll_state_data.position_y = viewport_point.y();
-  scroll_state_data.is_in_inertial_phase = true;
+  scroll_state_data.is_in_inertial_phase = false;
   ScrollState scroll_state(scroll_state_data);
 
   // ScrollAnimated is used for animated wheel scrolls. We find the first layer
@@ -2801,7 +2801,11 @@ InputHandler::ScrollStatus LayerTreeHostImpl::ScrollAnimatedBegin(
     ScrollStateData scroll_state_end_data;
     scroll_state_end_data.is_ending = true;
     ScrollState scroll_state_end(scroll_state_end_data);
+    // TODO(Sahel): Once the touchpad scroll latching for Non-mac devices is
+    // impelemented, the current scrolling layer should not get cleared after

[tdresser, 2016/08/31 13:10:05]

implemented

[sahel, 2016/08/31 14:25:10]

Done.

+    // each animation (crbug.com/526463).
     ScrollEnd(&scroll_state_end);
+    ClearCurrentlyScrollingLayer();

[ymalik, 2016/08/31 14:01:55]

I suspect that this is working correctly now because of your change above
(scroll_state_data.is_in_inertial_phase = false) and not because of your call to
ClearCurrentlyScrollingLayer().

Can you verify that this is the case?

If so, please update the description to better explain this case. 
  

[sahel, 2016/08/31 14:25:09]

It is working because of the call. The problem was that after calling
animatedBegin once and not clearing the scrolling layer, the second time that
animatedBegin was called, it would fall on the part that scroll gets ignored and
return before calling scrollBegin.

Correcting the is_in_initial_phase value is for scrollBegin function. In the
scrollBegin if the is_in_inertial_phase is true fling code is called, and that's
why is_in_initial_phase should be iff true in the case of a fling.

   }
   return scroll_status;
 }