[ChromeDriver] Support mobile emulation on desktop Chrome.

chrome/test/chromedriver/chrome_launcher.cc

 // 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.
 
 #include "chrome/test/chromedriver/chrome_launcher.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/base64.h"
@@ skipping 295 matching lines @@
                     "Chrome failed to start: " + termination_reason);
     }
     if (!base::KillProcess(process, 0, true)) {
       int exit_code;
       if (base::GetTerminationStatus(process, &exit_code) ==
           base::TERMINATION_STATUS_STILL_RUNNING)
         return Status(kUnknownError, "cannot kill Chrome", status);
     }
     return status;
   }
+  scoped_ptr<DeviceMetrics> device_metrics(
+      new DeviceMetrics(capabilities.device_metrics));
   scoped_ptr<ChromeDesktopImpl> chrome_desktop(
       new ChromeDesktopImpl(devtools_client.Pass(),
                             devtools_event_listeners,
                             port_reservation.Pass(),
                             process,
                             command,
+                            device_metrics.Pass(),
                             &user_data_dir,
                             &extension_dir));
   for (size_t i = 0; i < extension_bg_pages.size(); ++i) {
     VLOG(0) << "Waiting for extension bg page load: " << extension_bg_pages[i];
     scoped_ptr<WebView> web_view;
     Status status = chrome_desktop->WaitForPageToLoad(
         extension_bg_pages[i], base::TimeDelta::FromSeconds(10), &web_view);
     if (status.IsError()) {
       return Status(kUnknownError,
                     "failed to wait for extension background page to load: " +
@@ skipping 353 matching lines @@
   // Write empty "First Run" file, otherwise Chrome will wipe the default
   // profile that was written.
   if (base::WriteFile(
           user_data_dir.Append(chrome::kFirstRunSentinel), "", 0) != 0) {
     return Status(kUnknownError, "failed to write first run file");
   }
   return Status(kOk);
 }
 
 }  // namespace internal