[Chromedriver] Add Device Metrics override support to ChromeDriver via Capabilities

chrome/test/chromedriver/chrome/chrome_desktop_impl.h

 // Copyright (c) 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 CHROME_TEST_CHROMEDRIVER_CHROME_CHROME_DESKTOP_IMPL_H_
 #define CHROME_TEST_CHROMEDRIVER_CHROME_CHROME_DESKTOP_IMPL_H_
 
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 31 matching lines @@
                            scoped_ptr<WebView>* web_view);
 
   // Gets the installed automation extension.
   Status GetAutomationExtension(AutomationExtension** extension);
 
   // Overridden from Chrome:
   virtual ChromeDesktopImpl* GetAsDesktop() OVERRIDE;
   virtual std::string GetOperatingSystemName() OVERRIDE;
 
   // Overridden from ChromeImpl:
+  virtual bool IsMobileEmulationEnabled() const OVERRIDE;
   virtual Status QuitImpl() OVERRIDE;
 
   const base::CommandLine& command() const;
 
  private:
   base::ProcessHandle process_;
   base::CommandLine command_;
   base::ScopedTempDir user_data_dir_;
   base::ScopedTempDir extension_dir_;
 
   // Lazily initialized, may be null.
   scoped_ptr<AutomationExtension> automation_extension_;
 };
 
 #endif  // CHROME_TEST_CHROMEDRIVER_CHROME_CHROME_DESKTOP_IMPL_H_