Add Chrome Endure graph plotting code.

chrome/test/functional/perf/endure_graphs/js/common.js

+/*
+  Copyright (c) 2012 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.
+*/
+
+/**
+ * @fileoverview Common methods for performance-plotting Javascript.
+ */
+
+/**
+ * Fetches a URL asynchronously and invokes a callback when complete.
+ *
+ * @param {string} url URL to fetch.
+ * @param {Function(string, string)} callback The function to invoke when the
+ *     results of the URL fetch are complete.  The function should accept two
+ *     strings representing the URL data, and any errors, respectively.
+ */
+function Fetch(url, callback) {
+  var r = new XMLHttpRequest();
+  r.open('GET', url, true);
+  r.setRequestHeader('pragma', 'no-cache');
+  r.setRequestHeader('cache-control', 'no-cache');
+
+  r.onreadystatechange = function() {
+    if (r.readyState == 4) {
+      var text = r.responseText;
+      var error;
+      if (r.status != 200)
+        error = url + ': ' + r.status + ': ' + r.statusText;
+      else if (!text)
+        error = url + ': null response';
+      callback(text, error);
+    }
+  }
+
+  r.send(null);
+}
+
+/**
+ * Parses the parameters of the current page's URL.
+ *
+ * @return {Object} An object with properties given by the parameters specified
+ *     in the URL's query string.
+ */
+function ParseParams() {
+  var result = new Object();
+
+  var query = window.location.search.substring(1)
+  if (query.charAt(query.length - 1) == '/')
+    query = query.substring(0, query.length - 1)  // Strip trailing slash.
+  var s = query.split('&');
+
+  for (i = 0; i < s.length; ++i) {
+    var v = s[i].split('=');
+    var key = v[0];
+    var value = unescape(v[1]);
+    result[key] = value;
+  }
+
+  if ('history' in result) {
+    result['history'] = parseInt(result['history']);
+    result['history'] = Math.max(result['history'], 2);
+  }
+  if ('rev' in result) {
+    result['rev'] = parseInt(result['rev']);
+    result['rev'] = Math.max(result['rev'], -1);
+  }
+
+  return result;
+}
+
+/**
+ * Creates the URL constructed from the current pathname and the given params.
+ *
+ * @param {Object} An object containing parameters for a URL query string.
+ * @return {string} The URL constructed from the given params.
+ */
+function MakeURL(params) {
+  var url = window.location.pathname;
+  var sep = '?';
+  for (p in params) {
+    if (!p)
+      continue;
+    url += sep + p + '=' + params[p];
+    sep = '&';
+  }
+  return url;
+}