Use devtools to set user agent in chromedriver

chrome/test/chromedriver/chrome/chrome_desktop_impl.cc

Index: chrome/test/chromedriver/chrome/chrome_desktop_impl.cc
diff --git a/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc b/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc
index c6f843e7248da15778dad9de09bf9199f24a68c2..afc0c144671bac2b6b5371f876866a9ec69a9792 100644
--- a/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc
+++ b/chrome/test/chromedriver/chrome/chrome_desktop_impl.cc
@@ -148,10 +148,10 @@ Status ChromeDesktopImpl::WaitForPageToLoad(
     // https://code.google.com/p/chromedriver/issues/detail?id=1205
     device_metrics = nullptr;
   }
-  std::unique_ptr<WebView> web_view_tmp(
-      new WebViewImpl(id, w3c_compliant, devtools_http_client_->browser_info(),
-                      devtools_http_client_->CreateClient(id), device_metrics,
-                      page_load_strategy()));
+  std::unique_ptr<WebView> web_view_tmp(new WebViewImpl(
+      id, w3c_compliant, devtools_http_client_->browser_info(),
+      devtools_http_client_->CreateClient(id), device_metrics,
+      page_load_strategy(), devtools_http_client_->user_agent()));
   Status status = web_view_tmp->ConnectIfNecessary();
   if (status.IsError())
     return status;