DevTools: Use JS symbols instead of strings for eligible events.

third_party/WebKit/Source/devtools/front_end/emulation/EmulatedDevices.js

 // Copyright 2014 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.
 
 /**
  * @constructor
  */
 WebInspector.EmulatedDevice = function()
 {
     /** @type {string} */
@@ skipping 377 matching lines @@
     this._updateStandardDevices();
 
     /** @type {!WebInspector.Setting} */
     this._customSetting = WebInspector.settings.createSetting("customEmulatedDeviceList", []);
     /** @type {!Array.<!WebInspector.EmulatedDevice>} */
     this._custom = [];
     if (!this._listFromJSONV1(this._customSetting.get(), this._custom))
         this.saveCustomDevices();
 }
 
+/** @enum {symbol} */
 WebInspector.EmulatedDevicesList.Events = {
-    CustomDevicesUpdated: "CustomDevicesUpdated",
-    StandardDevicesUpdated: "StandardDevicesUpdated"
+    CustomDevicesUpdated: Symbol("CustomDevicesUpdated"),
+    StandardDevicesUpdated: Symbol("StandardDevicesUpdated")
 }
 
 WebInspector.EmulatedDevicesList.prototype = {
     _updateStandardDevices: function()
     {
         var devices = [];
         var extensions = self.runtime.extensions("emulated-device");
         for (var i = 0; i < extensions.length; ++i) {
             var device = WebInspector.EmulatedDevice.fromJSONV1(extensions[i].descriptor()["device"]);
             device.setExtension(extensions[i]);
@@ skipping 107 matching lines @@
 
 /**
  * @return {!WebInspector.EmulatedDevicesList}
  */
 WebInspector.EmulatedDevicesList.instance = function()
 {
     if (!WebInspector.EmulatedDevicesList._instance)
         WebInspector.EmulatedDevicesList._instance = new WebInspector.EmulatedDevicesList();
     return /** @type {!WebInspector.EmulatedDevicesList} */ (WebInspector.EmulatedDevicesList._instance);
 }