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

third_party/WebKit/Source/devtools/front_end/sdk/CSSModel.js

 /*
  * Copyright (C) 2010 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 43 matching lines @@
     /** @type {!Multimap<string, !CSSAgent.StyleSheetId>} */
     this._sourceMapLoadingStyleSheetsIds = new Multimap();
 
     /** @type {!Map<string, !WebInspector.SourceMap>} */
     this._sourceMapByURL = new Map();
     /** @type {!Multimap<string, !WebInspector.CSSStyleSheetHeader>} */
     this._sourceMapURLToHeaders = new Multimap();
     WebInspector.moduleSetting("cssSourceMapsEnabled").addChangeListener(this._toggleSourceMapSupport, this);
 }
 
+/** @enum {symbol} */
 WebInspector.CSSModel.Events = {
-    LayoutEditorChange: "LayoutEditorChange",
-    FontsUpdated: "FontsUpdated",
-    MediaQueryResultChanged: "MediaQueryResultChanged",
-    ModelWasEnabled: "ModelWasEnabled",
-    PseudoStateForced: "PseudoStateForced",
-    StyleSheetAdded: "StyleSheetAdded",
-    StyleSheetChanged: "StyleSheetChanged",
-    StyleSheetRemoved: "StyleSheetRemoved",
-    SourceMapAttached: "SourceMapAttached",
-    SourceMapDetached: "SourceMapDetached",
-    SourceMapChanged: "SourceMapChanged"
+    LayoutEditorChange: Symbol("LayoutEditorChange"),
+    FontsUpdated: Symbol("FontsUpdated"),
+    MediaQueryResultChanged: Symbol("MediaQueryResultChanged"),
+    ModelWasEnabled: Symbol("ModelWasEnabled"),
+    PseudoStateForced: Symbol("PseudoStateForced"),
+    StyleSheetAdded: Symbol("StyleSheetAdded"),
+    StyleSheetChanged: Symbol("StyleSheetChanged"),
+    StyleSheetRemoved: Symbol("StyleSheetRemoved"),
+    SourceMapAttached: Symbol("SourceMapAttached"),
+    SourceMapDetached: Symbol("SourceMapDetached"),
+    SourceMapChanged: Symbol("SourceMapChanged")
 }
 
 WebInspector.CSSModel.MediaTypes = ["all", "braille", "embossed", "handheld", "print", "projection", "screen", "speech", "tty", "tv"];
 
 WebInspector.CSSModel.PseudoStateMarker = "pseudo-state-marker";
 
 /**
  * @constructor
  * @param {!CSSAgent.StyleSheetId} styleSheetId
  * @param {!WebInspector.TextRange} oldRange
@@ skipping 1142 matching lines @@
 /**
  * @constructor
  * @param {?WebInspector.CSSStyleDeclaration} inlineStyle
  * @param {?WebInspector.CSSStyleDeclaration} attributesStyle
  */
 WebInspector.CSSModel.InlineStyleResult = function(inlineStyle, attributesStyle)
 {
     this.inlineStyle = inlineStyle;
     this.attributesStyle = attributesStyle;
 }