Allow MimeHandlerViewGuest be embedded inside OOPIFs

content/browser/frame_host/render_widget_host_view_guest.h

 // Copyright 2014 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_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_GUEST_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_GUEST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 109 matching lines @@
   void LockCompositingSurface() override;
   void UnlockCompositingSurface() override;
 
   void WheelEventAck(const blink::WebMouseWheelEvent& event,
                      InputEventAckState ack_result) override;
 
   void GestureEventAck(const blink::WebGestureEvent& event,
                        InputEventAckState ack_result) override;
 
   bool IsRenderWidgetHostViewGuest() override;
+  RenderWidgetHostViewBase* GetEmbedderView() override;
 
  protected:
   friend class RenderWidgetHostView;
 
  private:
   RenderWidgetHostViewGuest(
       RenderWidgetHost* widget,
       BrowserPluginGuest* guest,
       base::WeakPtr<RenderWidgetHostViewBase> platform_view);
 
@@ skipping 20 matching lines @@
   // The platform view for this RenderWidgetHostView.
   // RenderWidgetHostViewGuest mostly only cares about stuff related to
   // compositing, the rest are directly forwarded to this |platform_view_|.
   base::WeakPtr<RenderWidgetHostViewBase> platform_view_;
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewGuest);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_GUEST_H_