Generalize the net module's LoadLog facility from a passive container, to an event stream (NetLog).

chrome/browser/net/chrome_net_log.h

+// Copyright (c) 2010 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.
+
+#ifndef CHROME_BROWSER_NET_CHROME_NET_LOG_H_
+#define CHROME_BROWSER_NET_CHROME_NET_LOG_H_
+
+#include "base/observer_list.h"
+#include "net/base/net_log.h"
+
+class PassiveLogCollector;
+
+// ChromeNetLog is an implementation of NetLog that dispatches network log
+// messages to a list of observers.
+//
+// By default, ChromeNetLog will attach the observer PassiveLogCollector which
+// will keep track of recent request information (which used when displaying
+// the about:net-internals page).
+//
+// TODO(eroman): Move this default observer out of ChromeNetLog.
+//
+class ChromeNetLog : public net::NetLog {
+ public:
+  // Interface for observing the events logged by the network stack.
+  class Observer {
+   public:
+    virtual ~Observer() {}
+    virtual void OnAddEntry(const Entry& entry) = 0;
+  };
+
+  ChromeNetLog();
+  ~ChromeNetLog();
+
+  // NetLog implementation:
+  virtual void AddEntry(const Entry& entry);
+  virtual int NextID();
+  virtual bool HasListener() const;
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  PassiveLogCollector* passive_collector() {
+    return passive_collector_.get();
+  }
+
+ private:
+  int next_id_;
+  scoped_ptr<PassiveLogCollector> passive_collector_;
+  ObserverList<Observer, true> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeNetLog);
+};
+
+#endif  // CHROME_BROWSER_NET_CHROME_NET_LOG_H_