Allow MimeHandlerViewGuest be embedded inside OOPIFs

content/browser/frame_host/render_widget_host_view_guest.cc

 // 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.
 
 #include "content/browser/frame_host/render_widget_host_view_guest.h"
 
 #include <utility>
 
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
@@ skipping 235 matching lines @@
 }
 
 void RenderWidgetHostViewGuest::Destroy() {
   RenderWidgetHostViewChildFrame::Destroy();
 
   if (platform_view_)  // The platform view might have been destroyed already.
     platform_view_->Destroy();
 }
 
 gfx::Size RenderWidgetHostViewGuest::GetPhysicalBackingSize() const {
+  // We obtain the reference to native view from the owner RenderWidgetHostView.
+  // If the guest is embedded inside a cross-process frame, it is possible to
+  // reach here after the frame is detached in which case there will be no owner
+  // view.
+  if (!GetOwnerRenderWidgetHostView())
+    return gfx::Size();
   return RenderWidgetHostViewBase::GetPhysicalBackingSize();
 }
 
 base::string16 RenderWidgetHostViewGuest::GetSelectedText() {
   return platform_view_->GetSelectedText();
 }
 
 void RenderWidgetHostViewGuest::SetNeedsBeginFrames(
     bool needs_begin_frames) {
  if (platform_view_)
@@ skipping 415 matching lines @@
         gesture_event.data.scrollUpdate.inertialPhase ==
             blink::WebGestureEvent::MomentumPhase) {
       return;
     }
     host_->ForwardGestureEvent(gesture_event);
     return;
   }
 }
 
 }  // namespace content