[DevTools] Add 200ms timeout to menu on mousedown behavior.

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 626 matching lines @@
      * @override
      * @param {!Event} event
      */
     _mouseDown: function(event)
     {
         if (event.buttons !== 1) {
             WebInspector.ToolbarButton.prototype._mouseDown.call(this, event);
             return;
         }
 
+        if (!this._triggerTimeout)
+            this._triggerTimeout = setTimeout(this._trigger.bind(this, event), 200);
+    },
+
+    /**
+     * @param {!Event} event
+     */
+    _trigger: function(event)
+    {
+        delete this._triggerTimeout;

[PhistucK, 2016/03/16 18:04:48]

As far as I know, delete foo; is discouraged because it "rebuilds the world" (so
optimizations may have to be re-compiled?) and hurts performance.

Perhaps just this._triggerTimeout = 0;?

[pfeldman, 2016/03/16 19:33:31]

This code path will never be optimized in the first place and delete property is
something we carry from the WebKit times.

         var contextMenu = new WebInspector.ContextMenu(event,
             this._useSoftMenu,
             this.element.totalOffsetLeft(),
             this.element.totalOffsetTop() + this.element.offsetHeight);
         this._contextMenuHandler(contextMenu);
         contextMenu.show();
     },
 
     /**
      * @override
      * @param {!Event} event
      */
     _clicked: function(event)
     {
+        if (!this._triggerTimeout)
+            return;
+        clearTimeout(this._triggerTimeout);
+        this._trigger(event);
     },
 
     __proto__: WebInspector.ToolbarButton.prototype
 }
 
 /**
  * @constructor
  * @extends {WebInspector.ToolbarToggle}
  * @param {!WebInspector.Setting} setting
  * @param {string} glyph
@@ skipping 287 matching lines @@
     /**
      * @return {!Promise}
      */
     onLoad: function()
     {
         return this._promise;
     },
 
     __proto__: WebInspector.Toolbar.prototype
 }