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

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index 1b9f27687db42068aaa4d8027f8a78575125bdf9..bde7c86df08a7cde8e217d127df27844bd2aee22 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -559,6 +559,12 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost,
   // 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 PageGroupLoadDeferrers of any current dialogs are no
+  // longer on the stack when we attempt to swap it out.
+  void SuppressDialogsUntilSwapOut();
+
   // PlzNavigate: returns the LoFi state of the last successful navigation that
   // made a network request.
   LoFiState last_navigation_lofi_state() const {