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

third_party/WebKit/Source/devtools/front_end/ui/ResizerWidget.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
  * @extends {WebInspector.Object}
  */
 WebInspector.ResizerWidget = function()
 {
     WebInspector.Object.call(this);
 
     this._isEnabled = true;
     this._elements = [];
     this._installDragOnMouseDownBound = this._installDragOnMouseDown.bind(this);
     this._cursor = "nwse-resize";
 };
 
+/** @enum {symbol} */
 WebInspector.ResizerWidget.Events = {
-    ResizeStart: "ResizeStart",
-    ResizeUpdate: "ResizeUpdate",
-    ResizeEnd: "ResizeEnd"
+    ResizeStart: Symbol("ResizeStart"),
+    ResizeUpdate: Symbol("ResizeUpdate"),
+    ResizeEnd: Symbol("ResizeEnd")
 };
 
 WebInspector.ResizerWidget.prototype = {
     /**
      * @return {boolean}
      */
     isEnabled: function()
     {
         return this._isEnabled;
     },
@@ skipping 209 matching lines @@
     sendDragMove: function(startX, currentX, startY, currentY, shiftKey)
     {
         if (this._isVertical)
             this.dispatchEventToListeners(WebInspector.ResizerWidget.Events.ResizeUpdate, { startPosition: startY, currentPosition: currentY, shiftKey: shiftKey });
         else
             this.dispatchEventToListeners(WebInspector.ResizerWidget.Events.ResizeUpdate, { startPosition: startX, currentPosition: currentX, shiftKey: shiftKey });
     },
 
     __proto__: WebInspector.ResizerWidget.prototype
 };