[filebrowser] Historgram for the file browser's open time.

chrome/browser/resources/file_manager/js/metrics.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.
+
+/**
+ * @fileoverview Utility methods for accessing chrome.experimental.metrics API.
+ *
+ * To be included as a first script in main.html
+ */
+
+var metrics = {};
+
+metrics.intervals = {};
+
+metrics.startInterval = function(name) {
+  metrics.intervals[name] = Date.now();
+};
+
+metrics.startInterval('TotalLoad');
+metrics.startInterval('ScriptParse');
+
+metrics.convertName_ = function(name) {
+  // chrome.experimental.metrics will append extension ID after the last dot.
+  return 'FileBrowser.' + name + '.';
+};
+
+metrics.recordTime = function(name) {
+  if (name in metrics.intervals) {
+    var elapsed = Date.now() - metrics.intervals[name];
+    console.log(name + ': ' + elapsed + 'ms');
+    chrome.experimental.metrics.recordTime(metrics.convertName_(name), elapsed);
+  } else {
+    console.error('Unknown interval: ' + name);
+  }
+};
+
+metrics.recordAction = function(name) {
+  chrome.experimental.metrics.recordUserAction(metrics.convertName_(name));
+};