Use devtools to set user agent in chromedriver

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 <stddef.h>
 #include <stdint.h>
 #include <algorithm>
 #include <utility>
@@ skipping 174 matching lines @@
   std::unique_ptr<std::set<WebViewInfo::Type>> window_types;
   if (capabilities && !capabilities->window_types.empty()) {
     window_types.reset(
         new std::set<WebViewInfo::Type>(capabilities->window_types));
   } else {
     window_types.reset(new std::set<WebViewInfo::Type>());
   }
 
   std::unique_ptr<DevToolsHttpClient> client(new DevToolsHttpClient(
       address, context_getter, socket_factory, std::move(device_metrics),
-      std::move(window_types), capabilities->page_load_strategy));
+      std::move(window_types), capabilities->page_load_strategy,
+      capabilities->user_agent));
   base::TimeTicks deadline =
       base::TimeTicks::Now() + base::TimeDelta::FromSeconds(60);
   Status status = client->Init(deadline - base::TimeTicks::Now());
   if (status.IsError())
     return status;
 
   const BrowserInfo* browser_info = client->browser_info();
   if (browser_info->is_android &&
       browser_info->android_package != capabilities->android_package) {
     // DevTools from Chrome 30 and earlier did not provide an Android-Package
@@ skipping 675 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