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

third_party/WebKit/Source/devtools/front_end/components/HandlerRegistry.js

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 195 matching lines @@
         if (!targetNode.enclosingNodeOrSelfWithClassList(["resources", "panel"]) && WebInspector.resourceForURL(resourceURL))
             contextMenu.appendItem(WebInspector.UIString.capitalize("Open ^link in Resources ^panel"), openInResourcesPanel.bind(null, resourceURL));
 
 
         contextMenu.appendItem(WebInspector.copyLinkAddressLabel(), InspectorFrontendHost.copyText.bind(InspectorFrontendHost, resourceURL));
     },
 
     __proto__: WebInspector.Object.prototype
 }
 
-
+/** @enum {symbol} */
 WebInspector.HandlerRegistry.EventTypes = {
-    HandlersUpdated: "HandlersUpdated"
+    HandlersUpdated: Symbol("HandlersUpdated")
 }
 
 /**
  * @constructor
  */
 WebInspector.HandlerSelector = function(handlerRegistry)
 {
     this._handlerRegistry = handlerRegistry;
     this.element = createElementWithClass("select", "chrome-select");
     this.element.addEventListener("change", this._onChange.bind(this), false);
@@ skipping 88 matching lines @@
 
         var handlerSelector = new WebInspector.HandlerSelector(WebInspector.openAnchorLocationRegistry);
         return WebInspector.SettingsUI.createCustomSetting(WebInspector.UIString("Link handling:"), handlerSelector.element);
     }
 }
 
 /**
  * @type {!WebInspector.HandlerRegistry}
  */
 WebInspector.openAnchorLocationRegistry;