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

third_party/WebKit/Source/devtools/front_end/ui_lazy/OverviewGrid.js

 /*
  * Copyright (C) 2013 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 161 matching lines @@
     this._leftResizeElement = parentElement.createChild("div", "overview-grid-window-resizer");
     this._leftResizeElement.style.left = "0";
     WebInspector.installDragHandle(this._leftResizeElement, this._resizerElementStartDragging.bind(this), this._leftResizeElementDragging.bind(this), null, "ew-resize");
 
     this._rightResizeElement = parentElement.createChild("div", "overview-grid-window-resizer");
     this._rightResizeElement.style.right = "0";
     WebInspector.installDragHandle(this._rightResizeElement, this._resizerElementStartDragging.bind(this), this._rightResizeElementDragging.bind(this), null, "ew-resize");
     this.setEnabled(true);
 }
 
+/** @enum {symbol} */
 WebInspector.OverviewGrid.Events = {
-    WindowChanged: "WindowChanged",
-    Click: "Click"
+    WindowChanged: Symbol("WindowChanged"),
+    Click: Symbol("Click")
 }
 
 WebInspector.OverviewGrid.Window.prototype = {
     reset: function()
     {
         this.windowLeft = 0.0;
         this.windowRight = 1.0;
         this._leftResizeElement.style.left = "0%";
         this._rightResizeElement.style.left = "100%";
         this.setEnabled(true);
@@ skipping 264 matching lines @@
         position = Math.max(0, Math.min(position, this._width));
         if (position < this._startPosition) {
             this._windowSelector.style.left = position + "px";
             this._windowSelector.style.right = this._width - this._startPosition + "px";
         } else {
             this._windowSelector.style.left = this._startPosition + "px";
             this._windowSelector.style.right = this._width - position + "px";
         }
     }
 }