First step in enabling creating tabs without an Activity on Android.

content/shell/browser/shell_content_browser_client.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_SHELL_BROWSER_SHELL_CONTENT_BROWSER_CLIENT_H_
 #define CONTENT_SHELL_BROWSER_SHELL_CONTENT_BROWSER_CLIENT_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 45 matching lines @@
       WebContents* web_contents) override;
   QuotaPermissionContext* CreateQuotaPermissionContext() override;
   SpeechRecognitionManagerDelegate* CreateSpeechRecognitionManagerDelegate()
       override;
   net::NetLog* GetNetLog() override;
   bool ShouldSwapProcessesForRedirect(ResourceContext* resource_context,
                                       const GURL& current_url,
                                       const GURL& new_url) override;
   DevToolsManagerDelegate* GetDevToolsManagerDelegate() override;
 
-  WebContents* OpenURL(BrowserContext* browser_context,
-                       const OpenURLParams& params) override;
+  void OpenURL(BrowserContext* browser_context,
+               const OpenURLParams& params,
+               const base::Callback<void(WebContents*)>& callback) override;
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   void GetAdditionalMappedFilesForChildProcess(
       const base::CommandLine& command_line,
       int child_process_id,
       FileDescriptorInfo* mappings) override;
 #endif
 #if defined(OS_WIN)
   virtual void PreSpawnRenderer(sandbox::TargetPolicy* policy,
                                 bool* success) override;
@@ skipping 14 matching lines @@
 
   scoped_ptr<ShellResourceDispatcherHostDelegate>
       resource_dispatcher_host_delegate_;
 
   ShellBrowserMainParts* shell_browser_main_parts_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_BROWSER_SHELL_CONTENT_BROWSER_CLIENT_H_