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

third_party/WebKit/Source/devtools/front_end/timeline/PaintProfilerView.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 41 matching lines @@
     this._selectionWindow.addEventListener(WebInspector.OverviewGrid.Events.WindowChanged, this._onWindowChanged, this);
 
     this._innerBarWidth = 4 * window.devicePixelRatio;
     this._minBarHeight = window.devicePixelRatio;
     this._barPaddingWidth = 2 * window.devicePixelRatio;
     this._outerBarWidth = this._innerBarWidth + this._barPaddingWidth;
 
     this._reset();
 }
 
+/** @enum {symbol} */
 WebInspector.PaintProfilerView.Events = {
-    WindowChanged: "WindowChanged"
+    WindowChanged: Symbol("WindowChanged")
 };
 
 WebInspector.PaintProfilerView.prototype = {
     onResize: function()
     {
         this._update();
     },
 
     /**
      * @param {?WebInspector.PaintProfilerSnapshot} snapshot
@@ skipping 444 matching lines @@
     var method = logItem.method.toTitleCase();
 
     var logItemCategories = WebInspector.PaintProfilerView._initLogItemCategories();
     var result = logItemCategories[method];
     if (!result) {
         result = WebInspector.PaintProfilerView.categories()["misc"];
         logItemCategories[method] = result;
     }
     return result;
 }