Tons of timeline tweaks

chrome/browser/resources/tracing/measuring_stick.js

+// Copyright (c) 2011 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.
+
+cr.define('tracing', function() {
+  /**
+   * Uses an embedded iframe to measure provided elements without forcing layout
+   * on the main document.
+   * @constructor
+   * @extends {Object}
+   */
+  function MeasuringStick() {
+    var iframe = document.createElement('iframe');
+    iframe.style.cssText = 'width:100%;height:0;border:0;visibility:hidden';
+    document.body.appendChild(iframe);
+    this._doc = iframe.contentDocument;
+    this._window = iframe.contentWindow;
+    this._doc.body.style.cssText = 'padding:0;margin:0;overflow:hidden';
+
+    var stylesheets = document.querySelectorAll('link[rel=stylesheet]');
+    for (var i = 0; i < stylesheets.length; i++) {
+      var stylesheet = stylesheets[i];
+      var link = this._doc.createElement('link');
+      link.rel = 'stylesheet';
+      link.href = stylesheet.href;
+      this._doc.head.appendChild(link);
+    }
+  }
+
+  MeasuringStick.prototype = {
+    __proto__: Object.prototype,
+
+    /**
+     * Measures the provided element without forcing layout on the main
+     * document.
+     */
+    measure: function(element) {
+      this._doc.body.appendChild(element);
+      var style = this._window.getComputedStyle(element);
+      var width = parseInt(style.width, 10);
+      var height = parseInt(style.height, 10);
+      this._doc.body.removeChild(element);
+      return { width: width, height: height };
+    }
+  };
+
+  return {
+    MeasuringStick: MeasuringStick
+  };
+});