Fix layering violations in WebFrameWidget.

third_party/WebKit/Source/web/WebFrameWidgetBase.h

Index: third_party/WebKit/Source/web/WebFrameWidgetBase.h
diff --git a/third_party/WebKit/Source/web/WebFrameWidgetBase.h b/third_party/WebKit/Source/web/WebFrameWidgetBase.h
new file mode 100644
index 0000000000000000000000000000000000000000..e71ac932cd98197433eb25e0ecd953aaa40f6940
--- /dev/null
+++ b/third_party/WebKit/Source/web/WebFrameWidgetBase.h
@@ -0,0 +1,37 @@
+// Copyright 2016 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 WebFrameWidgetBase_h
+#define WebFrameWidgetBase_h
+
+#include "public/web/WebFrameWidget.h"
+#include "wtf/Assertions.h"
+
+namespace blink {
+
+class CompositorAnimationTimeline;
+class CompositorProxyClient;
+class GraphicsLayer;
+
+class WebFrameWidgetBase : public WebFrameWidget {
+public:
+    virtual bool forSubframe() const = 0;
+    virtual void scheduleAnimation() = 0;
+    virtual CompositorProxyClient* createCompositorProxyClient() = 0;
+    virtual WebWidgetClient* client() const = 0;
+
+    // Sets the root graphics layer. |GraphicsLayer| can be null when detaching
+    // the root layer.
+    virtual void setRootGraphicsLayer(GraphicsLayer*) = 0;
+
+    // Attaches/detaches a CompositorAnimationTimeline to the layer tree.
+    virtual void attachCompositorAnimationTimeline(CompositorAnimationTimeline*) = 0;
+    virtual void detachCompositorAnimationTimeline(CompositorAnimationTimeline*) = 0;
+};
+
+DEFINE_TYPE_CASTS(WebFrameWidgetBase, WebFrameWidget, widget, true, true);
+
+} // namespace blink
+
+#endif