Ensure that Metro chrome in ASH is able to connect to an existing desktop chrome AURA process.

chrome/test/base/testing_browser_process.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/test/base/testing_browser_process.h"
 
 #include "base/string_util.h"
 #include "build/build_config.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ skipping 267 matching lines @@
 
 BookmarkPromptController* TestingBrowserProcess::bookmark_prompt_controller() {
 #if defined(OS_IOS)
   NOTIMPLEMENTED();
   return NULL;
 #else
   return bookmark_prompt_controller_.get();
 #endif
 }
 
+void TestingBrowserProcess::PlatformSpecificCommandLineProcessing(
+    const CommandLine& command_line) {
+}
+
 void TestingBrowserProcess::SetBookmarkPromptController(
     BookmarkPromptController* controller) {
 #if !defined(OS_IOS)
   bookmark_prompt_controller_.reset(controller);
 #endif
 }
 
 void TestingBrowserProcess::SetSystemRequestContext(
     net::URLRequestContextGetter* context_getter) {
   system_request_context_ = context_getter;
@@ skipping 35 matching lines @@
 #endif
 }
 
 void TestingBrowserProcess::SetSafeBrowsingService(
     SafeBrowsingService* sb_service) {
 #if !defined(OS_IOS)
   NOTIMPLEMENTED();
   sb_service_ = sb_service;
 #endif
 }