Propagate opener to BackgroundsContents.

chrome/browser/android/document/document_web_contents_delegate.h

 // Copyright 2015 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 CHROME_BROWSER_ANDROID_DOCUMENT_DOCUMENT_WEB_CONTENTS_DELEGATE_H_
 #define CHROME_BROWSER_ANDROID_DOCUMENT_DOCUMENT_WEB_CONTENTS_DELEGATE_H_
 
 #include <stdint.h>
 
 #include "components/web_contents_delegate_android/web_contents_delegate_android.h"
@@ skipping 23 matching lines @@
   // Overridden from WebContentsDelegate.
   void AddNewContents(content::WebContents* source,
                       content::WebContents* new_contents,
                       WindowOpenDisposition disposition,
                       const gfx::Rect& initial_pos,
                       bool user_gesture,
                       bool* was_blocked) override;
   void CloseContents(content::WebContents* source) override;
   bool ShouldCreateWebContents(
       content::WebContents* web_contents,
+      content::RenderFrameHost* opener,
       content::SiteInstance* source_site_instance,
       int32_t route_id,
       int32_t main_frame_route_id,
       int32_t main_frame_widget_route_id,
       content::mojom::WindowContainerType window_container_type,
       const GURL& opener_url,
       const std::string& frame_name,
       const GURL& target_url,
       const std::string& partition_id,
       content::SessionStorageNamespace* session_storage_namespace) override;
 };
 
 #endif  // CHROME_BROWSER_ANDROID_DOCUMENT_DOCUMENT_WEB_CONTENTS_DELEGATE_H_