[ChromeDriver] Support mobile emulation on desktop Chrome.

chrome/test/chromedriver/capabilities.cc

Index: chrome/test/chromedriver/capabilities.cc
diff --git a/chrome/test/chromedriver/capabilities.cc b/chrome/test/chromedriver/capabilities.cc
index 518af52734a45f9c3537650db4f25ebdcaa5986d..53eeec385f5ee2649ec34f0c4a2452f432fbe3c4 100644
--- a/chrome/test/chromedriver/capabilities.cc
+++ b/chrome/test/chromedriver/capabilities.cc
@@ -84,6 +84,89 @@ Status ParseLogPath(const base::Value& option, Capabilities* capabilities) {
   return Status(kOk);
 }
 
+Status ParseDeviceName(std::string device_name, Capabilities* capabilities) {
+  // TODO(srawlins) Move this list into something auto-generated from WebKit.
+  std::map<std::string, MobileDevice> devices;
+  devices["Apple iPhone 3GS"] = MobileDevice(
+      DeviceMetrics(320, 480, 1),
+      "Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5");
+  // ...
+  devices["Google Nexus 4"] = MobileDevice(
+     DeviceMetrics(384, 640, 2),
+     "Mozilla/5.0 (Linux; Android 4.2.1; en-us; Nexus 4 Build/JOP40D) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.166 Mobile Safari/535.19");
+  devices["Google Nexus 5"] = MobileDevice(
+     DeviceMetrics(360, 640, 3),
+     "Mozilla/5.0 (Linux; Android 4.2.1; en-us; Nexus 5 Build/JOP40D) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.166 Mobile Safari/535.19");
+
+  std::map<std::string, MobileDevice>::iterator it = devices.find(device_name);
+
+  if (it == devices.end())
+    return Status(kUnknownError, "must be a valid device");

[samuong, 2014/05/07 23:39:36]

It would be good to also mention what the invalid device was in the error
message.

[sam.rawlins, 2014/05/09 05:35:17]

Done.

+
+  MobileDevice device = it->second;
+
+  capabilities->device_metrics.width = device.device_metrics.width;
+  capabilities->device_metrics.height = device.device_metrics.height;
+  capabilities->device_metrics.device_scale_factor =
+      device.device_metrics.device_scale_factor;
+  capabilities->device_metrics.emulate_viewport = false;
+  capabilities->device_metrics.fit_window = true;
+  capabilities->device_metrics.text_autosizing = true;
+  capabilities->device_metrics.font_scale_factor = 1;
+
+  capabilities->switches.SetUnparsedSwitch(
+      "--user-agent='" + device.user_agent + "'");
+
+  return Status(kOk);
+}
+
+Status ParseMobileEmulation(const base::Value& option,
+                     Capabilities* capabilities) {
+  const base::DictionaryValue* mobile_emulation;
+  if (!option.GetAsDictionary(&mobile_emulation))
+    return Status(kUnknownError, "must be a dictionary");

[samuong, 2014/05/07 23:39:36]

There are a few error messages that just say "must be a dictionary", and when
something fails it can be hard to figure out what the error message is referring
to. It would be good to mention what it is that must be a dictionary.

[sam.rawlins, 2014/05/09 05:35:17]

Done.

+
+  if (mobile_emulation->HasKey("deviceName")) {
+    // Cannot use any other options with deviceName
+    if (mobile_emulation->size() > 1)
+      return Status(kUnknownError, "'deviceName' must be used alone");
+
+    std::string device_name;
+    if (!mobile_emulation->GetString("deviceName", &device_name))
+      return Status(kUnknownError, "'deviceName' must be a string");
+
+    return ParseDeviceName(device_name, capabilities);
+  }
+
+  if (mobile_emulation->HasKey("deviceMetrics")) {
+    const base::DictionaryValue* metrics;
+    if (!mobile_emulation->GetDictionary("deviceMetrics", &metrics))
+      return Status(kUnknownError, "'deviceMetrics' must be a dictionary");
+
+    if (!metrics->GetInteger("width", &capabilities->device_metrics.width) ||
+        !metrics->GetInteger("height", &capabilities->device_metrics.height) ||
+        !metrics->GetDouble("pixelRatio",
+                            &capabilities->device_metrics.device_scale_factor))
+      return Status(kUnknownError, "invalid 'deviceMetrics'");
+
+    capabilities->device_metrics.emulate_viewport = false;
+    capabilities->device_metrics.fit_window = true;
+    capabilities->device_metrics.text_autosizing = true;
+    capabilities->device_metrics.font_scale_factor = 1;

[samuong, 2014/05/07 23:39:36]

This is done a few times. Should we put this in a constructor?

[sam.rawlins, 2014/05/09 05:35:17]

Done.

+  }
+
+  if (mobile_emulation->HasKey("userAgent")) {
+    std::string user_agent;
+    if (!mobile_emulation->GetString("userAgent", &user_agent))
+      return Status(kUnknownError, "'userAgent' must be a string");
+
+    capabilities->switches.SetUnparsedSwitch(
+        "--user-agent='" + user_agent + "'");
+  }
+
+  return Status(kOk);
+}
+
 Status ParseSwitches(const base::Value& option,
                      Capabilities* capabilities) {
   const base::ListValue* switches_list = NULL;
@@ -272,6 +355,8 @@ Status ParseChromeOptions(
     parser_map["args"] = base::Bind(&ParseSwitches);
     parser_map["binary"] = base::Bind(&ParseFilePath, &capabilities->binary);
     parser_map["detach"] = base::Bind(&ParseBoolean, &capabilities->detach);
+    parser_map["mobileEmulation"] =
+        base::Bind(&ParseMobileEmulation);

[samuong, 2014/05/07 23:39:36]

Can be one line.

[sam.rawlins, 2014/05/09 05:35:17]

Done.

     parser_map["excludeSwitches"] = base::Bind(&ParseExcludeSwitches);
     parser_map["extensions"] = base::Bind(&ParseExtensions);
     parser_map["forceDevToolsScreenshot"] = base::Bind(