[ChromeDriver] Support mobile emulation on desktop Chrome.

chrome/test/chromedriver/chrome_launcher.cc

Index: chrome/test/chromedriver/chrome_launcher.cc
diff --git a/chrome/test/chromedriver/chrome_launcher.cc b/chrome/test/chromedriver/chrome_launcher.cc
index ffc24283a8ccb1c37071241c1e607d0b4b081a5f..62d474e6f2f22efc6d2f26f65eb9bdac0062f967 100644
--- a/chrome/test/chromedriver/chrome_launcher.cc
+++ b/chrome/test/chromedriver/chrome_launcher.cc
@@ -156,9 +156,12 @@ Status WaitForDevToolsAndCheckVersion(
     const NetAddress& address,
     URLRequestContextGetter* context_getter,
     const SyncWebSocketFactory& socket_factory,
+    const Capabilities& capabilities,
     scoped_ptr<DevToolsHttpClient>* user_client) {
+  scoped_ptr<DeviceMetrics> device_metrics(
+      new DeviceMetrics(capabilities.device_metrics));
   scoped_ptr<DevToolsHttpClient> client(new DevToolsHttpClient(
-      address, context_getter, socket_factory));
+      address, context_getter, socket_factory, device_metrics.Pass()));
   base::TimeTicks deadline =
       base::TimeTicks::Now() + base::TimeDelta::FromSeconds(60);
   Status status = client->Init(deadline - base::TimeTicks::Now());
@@ -193,7 +196,7 @@ Status LaunchExistingChromeSession(
   scoped_ptr<DevToolsHttpClient> devtools_client;
   status = WaitForDevToolsAndCheckVersion(
       capabilities.debugger_address, context_getter, socket_factory,
-      &devtools_client);
+      capabilities, &devtools_client);

[stgao, 2014/05/14 05:10:14]

For this case "Existing Chrome Session", the browser is already launched, we
won't be able to set the command line switch "user-agent".

Maybe pass a NULL here.
In WaitForDevToolsAndCheckVersion check if it is NULL and do appropriate bailout
there.

[sam.rawlins, 2014/05/16 21:09:38]

Done.

   if (status.IsError()) {
     return Status(kUnknownError, "cannot connect to chrome at " +
                       capabilities.debugger_address.ToString(),
@@ -277,7 +280,8 @@ Status LaunchDesktopChrome(
 
   scoped_ptr<DevToolsHttpClient> devtools_client;
   status = WaitForDevToolsAndCheckVersion(
-      NetAddress(port), context_getter, socket_factory, &devtools_client);
+      NetAddress(port), context_getter, socket_factory, capabilities,
+      &devtools_client);
 
   if (status.IsError()) {
     int exit_code;
@@ -377,6 +381,7 @@ Status LaunchAndroidChrome(
   status = WaitForDevToolsAndCheckVersion(NetAddress(port),
                                           context_getter,
                                           socket_factory,
+                                          capabilities,
                                           &devtools_client);
   if (status.IsError()) {
     device->TearDown();