WebUI TaskManager: Delay scripts loading.

chrome/browser/resources/task_manager/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.metricsPrivate API.
+ *
+ * To be included as a first script in main.html
+ */
+
+var metrics = {};

[arv (Not doing code reviews), 2011/12/19 22:57:14]

I'm a bit confused. I thought this would do a chrome.send so we could get
histograms for this. Now I see that all it does is to print stuff to console.

console has API for timing things already and you could use that to reduce the
code here.

[yoshiki, 2011/12/20 15:18:25]

You're right. I intended to add recording histograms in future. But it has not
been implemented yet, so that I changed the file name and use console.time API
instead of console.log.

On 2011/12/19 22:57:14, arv wrote:

+
+metrics.intervals = {};
+
+metrics.startInterval = function(name) {
+  metrics.intervals[name] = Date.now();
+};
+
+metrics.startInterval('Load.Total');
+metrics.startInterval('Load.Script');
+
+metrics.convertName_ = function(name) {
+  return 'TaskManager.' + name;
+};
+
+metrics.decorate = function(name) {
+  this[name] = function() {
+    var args = Array.apply(null, arguments);

[arv (Not doing code reviews), 2011/12/19 22:57:14]

This is error prone. If argument.length == 1 and arguments[0] is a number it
will use that as the length.

A better way is to use slice

var args = Array.prototype.slice.call(arguments);

but it is unclear why you want to convert the argument object to a normal array
here?

+    args[0] = metrics.convertName_(args[0]);
+
+    // TODO(yoshiki): Enables the recoading metrixes of loading times.

[arv (Not doing code reviews), 2011/12/19 22:57:14]

Is "metrixes" a real word?

+    // chrome.metricsPrivate[name].apply(chrome.metricsPrivate, args);

[arv (Not doing code reviews), 2011/12/19 22:57:14]

Look into chrome.send. We already have a chrome send for UMA stats.

+
+    // Outputs log to Console in inspector if the flag is enabled.
+    if (localStorage.logMetrics) {

[arv (Not doing code reviews), 2011/12/19 22:57:14]

no {} here

+      console.log('chrome.metricsPrivate.' + name, args);
+    }
+  }
+};
+
+metrics.decorate('recordMediumCount');
+metrics.decorate('recordSmallCount');
+metrics.decorate('recordTime');
+metrics.decorate('recordUserAction');
+
+metrics.recordInterval = function(name) {
+  if (name in metrics.intervals) {

[James Hawkins, 2011/12/19 18:35:56]

Remove braces.

+    metrics.recordTime(name, Date.now() - metrics.intervals[name]);
+  } else {
+    console.error('Unknown interval: ' + name);
+  }
+};