Fix JavaScript alerts from frames with oopif on, after a cross-process click.

content/browser/frame_host/render_frame_host_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_RENDER_FRAME_HOST_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 541 matching lines @@
   // Destroys all WebUI instances and resets related data.
   void ClearAllWebUI();
 
   // Returns the Mojo ImageDownloader service.
   const content::mojom::ImageDownloaderPtr& GetMojoImageDownloader();
 
   // Resets the loading state. Following this call, the RenderFrameHost will be
   // in a non-loading state.
   void ResetLoadingState();
 
+  // Tells the renderer that this RenderFrame will soon be swapped out, and thus
+  // not to create any new modal dialogs until it happens.  This must be done
+  // separately so that the ScopedPageLoadDeferrers of any current dialogs are
+  // no longer on the stack when we attempt to swap it out.
+  void SuppressFurtherDialogs();
+
   // PlzNavigate: returns the LoFi state of the last successful navigation that
   // made a network request.
   LoFiState last_navigation_lofi_state() const {
     return last_navigation_lofi_state_;
   }
 
  protected:
   friend class RenderFrameHostFactory;
 
   // |flags| is a combination of CreateRenderFrameFlags.
@@ skipping 404 matching lines @@
 
   // NOTE: This must be the last member.
   base::WeakPtrFactory<RenderFrameHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_