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

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

 /*
  * Copyright (C) 2008 Apple Inc.  All rights reserved.
  * 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 31 matching lines @@
     this._proxyElement;
     this._proxyElementDisplay = "inline-block";
     this._loadCompletions = completions;
     this._completionStopCharacters = stopCharacters || " =:[({;,!+-*/&|^<>.";
     this._autocompletionTimeout = WebInspector.TextPrompt.DefaultAutocompletionTimeout;
     this._title = "";
 }
 
 WebInspector.TextPrompt.DefaultAutocompletionTimeout = 250;
 
+/** @enum {symbol} */
 WebInspector.TextPrompt.Events = {
-    ItemApplied: "text-prompt-item-applied",
-    ItemAccepted: "text-prompt-item-accepted"
+    ItemApplied: Symbol("text-prompt-item-applied"),
+    ItemAccepted: Symbol("text-prompt-item-accepted")
 };
 
 WebInspector.TextPrompt.prototype = {
     /**
      * @param {number} timeout
      */
     setAutocompletionTimeout: function(timeout)
     {
         this._autocompletionTimeout = timeout;
     },
@@ skipping 964 matching lines @@
     },
 
     /**
      * @return {string|undefined}
      */
     _currentHistoryItem: function()
     {
         return this._data[this._data.length - this._historyOffset];
     }
 };