Allow a main interstitial frame to act as an ExtensionMessagePort opener

content/browser/frame_host/interstitial_page_impl.h

 // Copyright 2013 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_INTERSTITIAL_PAGE_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_INTERSTITIAL_PAGE_IMPL_H_
 
 #include <stdint.h>
 
 #include "base/compiler_specific.h"
@@ skipping 46 matching lines @@
                        bool new_navigation,
                        const GURL& url,
                        InterstitialPageDelegate* delegate);
   ~InterstitialPageImpl() override;
 
   // InterstitialPage implementation:
   void Show() override;
   void Hide() override;
   void DontProceed() override;
   void Proceed() override;
+  WebContents* GetWebContents() const override;
   RenderFrameHost* GetMainFrame() const override;
   InterstitialPageDelegate* GetDelegateForTesting() override;
   void DontCreateViewForTesting() override;
   void SetSize(const gfx::Size& size) override;
   void Focus() override;
 
   // Allows the user to navigate away by disabling the interstitial, canceling
   // the pending request, and unblocking the hidden renderer.  The interstitial
   // will stay visible until the navigation completes.
   void CancelForNavigation();
@@ skipping 23 matching lines @@
                const NotificationDetails& details) override;
 
   // RenderFrameHostDelegate implementation:
   bool OnMessageReceived(RenderFrameHost* render_frame_host,
                          const IPC::Message& message) override;
   void RenderFrameCreated(RenderFrameHost* render_frame_host) override;
   void UpdateTitle(RenderFrameHost* render_frame_host,
                    int32_t page_id,
                    const base::string16& title,
                    base::i18n::TextDirection title_direction) override;
+  InterstitialPage* GetAsInterstitialPage() override;
   AccessibilityMode GetAccessibilityMode() const override;
   void Cut() override;
   void Copy() override;
   void Paste() override;
   void SelectAll() override;
 
   // RenderViewHostDelegate implementation:
   RenderViewHostDelegateView* GetDelegateView() override;
   bool OnMessageReceived(RenderViewHost* render_view_host,
                          const IPC::Message& message) override;
@@ skipping 174 matching lines @@
   scoped_refptr<SessionStorageNamespace> session_storage_namespace_;
 
   base::WeakPtrFactory<InterstitialPageImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(InterstitialPageImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_INTERSTITIAL_PAGE_IMPL_H_