RenderWidget/RenderView: encapsulate ViewHostMsg_Show, etc, in a callback

content/renderer/render_widget_fullscreen.h

-// Copyright (c) 2012 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 CONTENT_RENDERER_RENDER_WIDGET_FULLSCREEN_H_
-#define CONTENT_RENDERER_RENDER_WIDGET_FULLSCREEN_H_
-
-#include "content/renderer/render_widget.h"
-
-#include <stdint.h>
-
-#include "third_party/WebKit/public/web/WebWidget.h"
-
-namespace content {
-class CompositorDependencies;
-
-// TODO(boliu): Override non-supported methods with no-op? eg setWindowRect().
-class RenderWidgetFullscreen : public RenderWidget {
- public:
-  void show(blink::WebNavigationPolicy) override;
-
- protected:
-  static int32_t CreateFullscreenWidgetRoutingId(int32_t opener_id);
-
-  RenderWidgetFullscreen(int32_t widget_routing_id,
-                         CompositorDependencies* compositor_deps,
-                         const ScreenInfo& screen_info);
-  ~RenderWidgetFullscreen() override;
-
-  virtual blink::WebWidget* CreateWebWidget();
-
-  bool Init(int32_t opener_id);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_RENDER_WIDGET_FULLSCREEN_H_