Revert of [DevTools] Remove methods on Common.Event.

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

 /*
  * Copyright (C) 2009 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 493 matching lines @@
     var dropdownArrowIcon = UI.Icon.create('smallicon-dropdown-arrow', 'toolbar-dropdown-arrow');
     this.element.appendChild(dropdownArrowIcon);
     if (width)
       this.element.style.width = width + 'px';
   }
 
   /**
    * @param {!Event} event
    */
   _clicked(event) {
-    this.dispatchEventToListeners(UI.ToolbarButton.Events.Click, event);
+    var defaultPrevented = this.dispatchEventToListeners('click', event);
+    event.consume(defaultPrevented);
   }
 
   /**
    * @param {!Event} event
    */
   _mouseDown(event) {
-    this.dispatchEventToListeners(UI.ToolbarButton.Events.MouseDown, event);
+    this.dispatchEventToListeners('mousedown', event);
   }
 
   /**
    * @param {!Event} event
    */
   _mouseUp(event) {
-    this.dispatchEventToListeners(UI.ToolbarButton.Events.MouseUp, event);
+    this.dispatchEventToListeners('mouseup', event);
   }
 };
 
-UI.ToolbarButton.Events = {
-  Click: Symbol('Click'),
-  MouseDown: Symbol('MouseDown'),
-  MouseUp: Symbol('MouseUp')
-};
-
 /**
  * @unrestricted
  */
 UI.ToolbarInput = class extends UI.ToolbarItem {
   /**
    * @param {string=} placeholder
    * @param {number=} growFactor
    */
   constructor(placeholder, growFactor) {
     super(createElementWithClass('input', 'toolbar-item'));
@@ skipping 19 matching lines @@
   value() {
     return this.element.value;
   }
 
   _onChangeCallback() {
     this.dispatchEventToListeners(UI.ToolbarInput.Event.TextChanged, this.element.value);
   }
 };
 
 UI.ToolbarInput.Event = {
-  TextChanged: Symbol('TextChanged')
+  TextChanged: 'TextChanged'
 };
 
 /**
  * @unrestricted
  */
 UI.ToolbarToggle = class extends UI.ToolbarButton {
   /**
    * @param {string} title
    * @param {string=} glyph
    * @param {string=} toggledGlyph
@@ skipping 313 matching lines @@
     return this.inputElement.checked;
   }
 
   /**
    * @param {boolean} value
    */
   setChecked(value) {
     this.inputElement.checked = value;
   }
 };