Allow MimeHandlerViewGuest be embedded inside OOPIFs

components/guest_view/browser/guest_view_base.h

Index: components/guest_view/browser/guest_view_base.h
diff --git a/components/guest_view/browser/guest_view_base.h b/components/guest_view/browser/guest_view_base.h
index 320a5e4d50b269831aeb861b657a7c3d3f4646df..9af5769c4c4e042ded225e3c4f9cff2a337e3c0d 100644
--- a/components/guest_view/browser/guest_view_base.h
+++ b/components/guest_view/browser/guest_view_base.h
@@ -200,6 +200,10 @@ class GuestViewBase : public content::BrowserPluginGuestDelegate,
   void SetAttachParams(const base::DictionaryValue& params);
   void SetOpener(GuestViewBase* opener);
 
+  // BrowserPluginGuestDelegate implementation.
+  content::RenderWidgetHost* GetOwnerRenderWidgetHost() override;
+  content::SiteInstance* GetOwnerSiteInstance() override;
+
  protected:
   explicit GuestViewBase(content::WebContents* owner_web_contents);
 
@@ -208,6 +212,10 @@ class GuestViewBase : public content::BrowserPluginGuestDelegate,
   // BrowserPluginGuestDelegate implementation.
   void SetContextMenuPosition(const gfx::Point& position) override;
 
+  // Notifies the guest the a given RenderFrameHost in the owner WebContents is
+  // deleted. this is needed.
+  virtual void OnRenderFrameHostDeleted(int process_id, int routing_id);
+
   // WebContentsDelegate implementation.
   void HandleKeyboardEvent(
       content::WebContents* source,