Implement CSS: scroll-boundary-behavior

third_party/WebKit/public/platform/WebScrollBoundaryBehavior.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WebScrollBoundaryBehavior_h
+#define WebScrollBoundaryBehavior_h
+
+namespace blink {
+
+enum WebScrollBoundaryBehavior {
+
+  WebScrollBoundaryBehaviorPropagate,

[bokan, 2017/03/23 13:18:26]

Also check these in Source/web/AssertMatchingEnums.cpp

[sunyunjia, 2017/03/23 20:16:55]

Feels like AssertMatchingEnums.cpp is checking WebXXX vs XXX, both in blink
side. 

Now I added a check in web_layer_impl.cc, as those are checked at
render_widget_compositor.cc, is it the right place to do that?

[bokan, 2017/03/23 21:52:19]

Actually, I think you can just get rid of the WebXXX version altogether. See how
this is done for WebKit/Source/platform/scroll/MainThreadScrollingReason.h. Then
you can just static_assert those vs the one defined for Style.

+
+  WebScrollBoundaryBehaviorContain,
+
+  WebScrollBoundaryBehaviorNone
+
+};
+
+}  // namespace blink
+#endif