Implement CSS: scroll-boundary-behavior

third_party/WebKit/public/platform/WebLayer.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 18 matching lines @@
 #include "cc/layers/layer.h"
 
 #include "WebBlendMode.h"
 #include "WebColor.h"
 #include "WebCommon.h"
 #include "WebFloatPoint.h"
 #include "WebFloatPoint3D.h"
 #include "WebFloatSize.h"
 #include "WebPoint.h"
 #include "WebRect.h"
+#include "WebScrollBoundaryBehavior.h"
 #include "WebSize.h"
 #include "WebString.h"
 #include "WebTouchInfo.h"
 #include "WebVector.h"
 
 class SkMatrix44;
 
 namespace cc {
 class Layer;
 class LayerClient;
@@ skipping 156 matching lines @@
       const WebLayerStickyPositionConstraint&) = 0;
   virtual WebLayerStickyPositionConstraint StickyPositionConstraint() const = 0;
 
   // The scroll client is notified when the scroll position of the WebLayer
   // changes. Only a single scroll client can be set for a WebLayer at a time.
   // The WebLayer does not take ownership of the scroll client, and it is the
   // responsibility of the client to reset the layer's scroll client before
   // deleting the scroll client.
   virtual void SetScrollClient(WebLayerScrollClient*) = 0;
 
+  virtual void SetScrollBoundaryBehavior(const WebScrollBoundaryBehavior&) = 0;

[Rick Byers, 2017/07/18 18:44:25]

nit: please add a comment describing at a high level the purpose of this API. 
We try to make the public API be fairly well documented (compared to other areas
of blink) - eg. there are chromium developers who will use public/ APIs but
never look at any of the code underneath it.

+
   // Sets the cc-side layer client.
   virtual void SetLayerClient(cc::LayerClient*) = 0;
 
   // Gets the underlying cc layer.
   virtual const cc::Layer* CcLayer() const = 0;
   virtual cc::Layer* CcLayer() = 0;
 
   virtual void SetElementId(const cc::ElementId&) = 0;
   virtual cc::ElementId GetElementId() const = 0;
 
   virtual void SetCompositorMutableProperties(uint32_t) = 0;
   virtual uint32_t CompositorMutableProperties() const = 0;
 
   virtual void SetHasWillChangeTransformHint(bool) = 0;
 
   // Called on the scroll layer to trigger showing the overlay scrollbars.
   virtual void ShowScrollbars() = 0;
 };
 
 }  // namespace blink
 
 #endif  // WebLayer_h