[refactor] Split up SourceTracker into SourceTracker + EventsTracker.

chrome/browser/resources/net_internals/events_tracker.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 EventsTracker = (function() {
+  'use strict';
+
+  /**
+   * This class keeps track of all NetLog events.
+   * It receives events from the browser and when loading a log file, and passes
+   * them on to all its observers.
+   *
+   * @constructor
+   */
+  function EventsTracker() {
+    assertFirstConstructorCall(EventsTracker);
+
+    this.capturedEvents_ = [];
+    this.observers_ = [];
+  }
+
+  cr.addSingletonGetter(EventsTracker);
+
+  EventsTracker.prototype = {
+    /**
+     * Returns a list of all captured events.
+     */
+    getAllCapturedEvents: function() {
+      return this.capturedEvents_;
+    },
+
+    /**
+     * Returns the number of events that were captured.
+     */
+    getNumCapturedEvents: function() {
+      return this.capturedEvents_.length;
+    },
+
+    /**
+     * Deletes all the tracked events, and notifies any observers.
+     */
+    deleteAllLogEntries: function() {
+      this.capturedEvents_ = [];
+      for (var i = 0; i < this.observers_.length; ++i)
+        this.observers_[i].onAllLogEntriesDeleted();
+    },
+
+    /**
+     * Adds captured events, and broadcasts them to any observers.
+     */
+    addLogEntries: function(logEntries) {
+      this.capturedEvents_ = this.capturedEvents_.concat(logEntries);
+      for (var i = 0; i < this.observers_.length; ++i) {
+        this.observers_[i].onReceivedLogEntries(logEntries);
+      }
+    },
+
+    /**
+     * Adds a listener of log entries. |observer| will be called back when new
+     * log data arrives or all entries are deleted:
+     *
+     *   observer.onReceivedLogEntries(entries)
+     *   observer.onAllLogEntriesDeleted()
+     */
+    addLogEntryObserver: function(observer) {
+      this.observers_.push(observer);
+    }
+  };
+
+  return EventsTracker;
+})();