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

third_party/WebKit/Source/devtools/front_end/elements/BezierEditor.js

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @constructor
  * @extends {WebInspector.VBox}
  */
 WebInspector.BezierEditor = function()
 {
@@ skipping 25 matching lines @@
     WebInspector.installDragHandle(this._curve, this._dragStart.bind(this), this._dragMove.bind(this), this._dragEnd.bind(this), "default");
 
     this._header = this.contentElement.createChild("div", "bezier-header");
     var minus = this._createPresetModifyIcon(this._header, "bezier-preset-minus", "M 12 6 L 8 10 L 12 14");
     var plus = this._createPresetModifyIcon(this._header, "bezier-preset-plus", "M 8 6 L 12 10 L 8 14");
     minus.addEventListener("click", this._presetModifyClicked.bind(this, false));
     plus.addEventListener("click", this._presetModifyClicked.bind(this, true));
     this._label = this._header.createChild("span", "source-code bezier-display-value");
 }
 
+/** @enum {symbol} */
 WebInspector.BezierEditor.Events = {
-    BezierChanged: "BezierChanged"
+    BezierChanged: Symbol("BezierChanged")
 }
 
 WebInspector.BezierEditor.Presets = [
     [
         { name: "ease-in-out", value: "ease-in-out" },
         { name: "In Out · Sine", value: "cubic-bezier(0.45, 0.05, 0.55, 0.95)" },
         { name: "In Out · Quadratic", value: "cubic-bezier(0.46, 0.03, 0.52, 0.96)" },
         { name: "In Out · Cubic", value: "cubic-bezier(0.65, 0.05, 0.36, 1)" },
         { name: "Fast Out, Slow In", value: "cubic-bezier(0.4, 0, 0.2, 1)" },
         { name: "In Out · Back", value: "cubic-bezier(0.68, -0.55, 0.27, 1.55)" }
@@ skipping 214 matching lines @@
             var slice = this._previewOnion.createChild("div", "bezier-preview-animation");
             var player = slice.animate([{ transform: "translateX(0px)", easing: this._bezier.asCSSText() }, { transform: "translateX(218px)" }],
                 { duration: animationDuration, fill: "forwards" });
             player.pause();
             player.currentTime = animationDuration * i / numberOnionSlices;
         }
     },
 
     __proto__: WebInspector.VBox.prototype
 }