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

third_party/WebKit/Source/devtools/front_end/ui/SplitWidget.js

 /*
  * Copyright (C) 2012 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 60 matching lines @@
 
 /** @typedef {{showMode: string, size: number}} */
 WebInspector.SplitWidget.SettingForOrientation;
 
 WebInspector.SplitWidget.ShowMode = {
     Both: "Both",
     OnlyMain: "OnlyMain",
     OnlySidebar: "OnlySidebar"
 }
 
+/** @enum {symbol} */
 WebInspector.SplitWidget.Events = {
-    SidebarSizeChanged: "SidebarSizeChanged",
-    ShowModeChanged: "ShowModeChanged"
+    SidebarSizeChanged: Symbol("SidebarSizeChanged"),
+    ShowModeChanged: Symbol("ShowModeChanged")
 }
 
 WebInspector.SplitWidget.MinPadding = 20;
 
 WebInspector.SplitWidget.prototype = {
     /**
      * @return {boolean}
      */
     isVertical: function()
     {
@@ skipping 823 matching lines @@
         this._showHideSidebarButton.classList.toggle("toggled-hide", !sidebarHidden);
         this._showHideSidebarButton.classList.toggle("top-sidebar-show-hide-button", !this.isVertical() && !this.isSidebarSecond());
         this._showHideSidebarButton.classList.toggle("right-sidebar-show-hide-button", this.isVertical() && this.isSidebarSecond());
         this._showHideSidebarButton.classList.toggle("bottom-sidebar-show-hide-button", !this.isVertical() && this.isSidebarSecond());
         this._showHideSidebarButton.classList.toggle("left-sidebar-show-hide-button", this.isVertical() && !this.isSidebarSecond());
         this._showHideSidebarButton.title = sidebarHidden ? WebInspector.UIString("Show %s", this._showHideSidebarButtonTitle) : WebInspector.UIString("Hide %s", this._showHideSidebarButtonTitle);
     },
 
     __proto__: WebInspector.Widget.prototype
 }