Add logging for ResourceScheduler events.

chrome/browser/resources/net_internals/source_entry.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.
 
 var SourceEntry = (function() {
   'use strict';
 
   /**
    * A SourceEntry gathers all log entries with the same source.
    *
@@ skipping 168 matching lines @@
      * in the list view. Most often this is a URL that identifies the request,
      * or a hostname for a connect job, etc...
      */
     getDescription: function() {
       return this.description_;
     },
 
     /**
      * Returns the starting entry for this source. Conceptually this is the
      * first entry that was logged to this source. However, we skip over the
-     * TYPE_REQUEST_ALIVE entries which wrap TYPE_URL_REQUEST_START_JOB
-     * entries.
+     * TYPE_REQUEST_ALIVE entries without parameters which wrap
+     * TYPE_URL_REQUEST_START_JOB entries.  (TYPE_REQUEST_ALIVE may or may not
+     * have parameters depending on what version of Chromium they were
+     * generated from.)
      */
     getStartEntry_: function() {
       if (this.entries_.length < 1)
         return undefined;
       if (this.entries_[0].source.type == EventSourceType.FILESTREAM) {
         var e = this.findLogEntryByType_(EventType.FILE_STREAM_OPEN);
         if (e != undefined)
           return e;
       }
       if (this.entries_[0].source.type == EventSourceType.DOWNLOAD) {
@@ skipping 145 matching lines @@
           this.entries_,
           SourceTracker.getInstance().getPrivacyStripping(),
           SourceTracker.getInstance().getUseRelativeTimes() ?
               timeutil.getBaseTime() : 0,
           Constants.clientInfo.numericDate);
     },
   };
 
   return SourceEntry;
 })();