phase based wheel scroll latching for mac

content/browser/renderer_host/render_widget_host_view_mac.h

Index: content/browser/renderer_host/render_widget_host_view_mac.h
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.h b/content/browser/renderer_host/render_widget_host_view_mac.h
index ac198a442454506a9caf84b3b7a029576ba257cf..4362092c21ff0f6206b7b73ebc433787c766575b 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.h
+++ b/content/browser/renderer_host/render_widget_host_view_mac.h
@@ -487,6 +487,16 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
   // Get the focused view that should be used for retrieving the text selection.
   RenderWidgetHostViewBase* GetFocusedViewForTextSelection();
 
+  bool WheelScrollLatchingEnabled() { return wheel_scroll_latching_enabled_; }

[tdresser, 2017/05/25 15:18:36]

Is this needed? It appears redundant with
https://cs.chromium.org/chromium/src/content/browser/renderer_host/render_wid...

[sahel, 2017/05/25 16:00:04]

Done.

+
+  base::OneShotTimer mouse_wheel_end_dispatch_timer_;

[tdresser, 2017/05/25 15:18:36]

Make private.

[sahel, 2017/05/25 16:00:04]

This is Stopped in RenderWidgetHostViewCocoa, should I make it private and add a
public function that stops this timer?

[tdresser, 2017/05/25 19:34:48]

Yup. The fact that this is implemented via a timer is arguably an implementation
detail that shouldn't be exposed, so you might want to name it more
semantically.

Maybe we need two methods, like "DispatchPendingWheelEndEvent" and
"IgnorePendingWheelEndEvent"?

+
+  void SendSyntheticWheelEventWithPhaseEnded(
+      blink::WebMouseWheelEvent wheel_event,
+      bool should_route_event);

[tdresser, 2017/05/25 15:18:36]

Can this be private?

[sahel, 2017/05/25 16:00:04]

This is called in RenderWidgetHostViewCocoa, cannot be private. 

[tdresser, 2017/05/25 19:34:48]

It is? Isn't it only called in
RenderWidgetHostViewMac::StartMouseWheelEndDispatchTimer?

[sahel, 2017/05/26 18:03:25]

Done.

+  void StartMouseWheelEndDispatchTimer(blink::WebMouseWheelEvent wheel_event,
+                                       bool should_route_event);

[tdresser, 2017/05/25 15:18:36]

Can this be private?

[sahel, 2017/05/25 16:00:04]

This is called in RenderWidgetHostViewCocoa, cannot be private.

[tdresser, 2017/05/25 19:34:47]

Acknowledged.

+
   // Returns the RenderWidgetHostDelegate corresponding to the currently focused
   // RenderWidgetHost. It is different from |render_widget_host_->delegate()|
   // when there are focused inner WebContentses on the page. Also, this method