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

third_party/WebKit/Source/devtools/front_end/sources/TabbedEditorContainer.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:
  *
  * 1. Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *
@@ skipping 52 matching lines @@
     this._tabbedPane.addEventListener(WebInspector.TabbedPane.EventTypes.TabClosed, this._tabClosed, this);
     this._tabbedPane.addEventListener(WebInspector.TabbedPane.EventTypes.TabSelected, this._tabSelected, this);
 
     this._tabIds = new Map();
     this._files = {};
 
     this._previouslyViewedFilesSetting = setting;
     this._history = WebInspector.TabbedEditorContainer.History.fromObject(this._previouslyViewedFilesSetting.get());
 }
 
+/** @enum {symbol} */
 WebInspector.TabbedEditorContainer.Events = {
-    EditorSelected: "EditorSelected",
-    EditorClosed: "EditorClosed"
+    EditorSelected: Symbol("EditorSelected"),
+    EditorClosed: Symbol("EditorClosed")
 }
 
 WebInspector.TabbedEditorContainer._tabId = 0;
 
 WebInspector.TabbedEditorContainer.maximalPreviouslyViewedFilesCount = 30;
 
 WebInspector.TabbedEditorContainer.prototype = {
     /**
      * @return {!WebInspector.Widget}
      */
@@ skipping 664 matching lines @@
     /**
      * @override
      * @param {string} tabId
      * @param {!WebInspector.ContextMenu} contextMenu
      */
     onContextMenu: function(tabId, contextMenu)
     {
         this._editorContainer._onContextMenu(tabId, contextMenu);
     }
 }