Update NetLog to be thread safe.

chrome/browser/debugger/devtools_netlog_observer.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_DEBUGGER_DEVTOOLS_NETLOG_OBSERVER_H_
 #define CHROME_BROWSER_DEBUGGER_DEVTOOLS_NETLOG_OBSERVER_H_
 #pragma once
 
 #include "base/hash_tables.h"
 #include "base/ref_counted.h"
 #include "chrome/browser/net/chrome_net_log.h"
 #include "webkit/glue/resource_loader_bridge.h"
 
 class IOThread;
 class URLRequest;
 struct ResourceResponse;
 
 // DevToolsNetLogObserver watches the NetLog event stream and collects the
 // stuff that may be of interest to DevTools. Currently, this only includes
 // actual HTTP/SPDY headers sent and received over the network.
-class DevToolsNetLogObserver: public ChromeNetLog::Observer {
+//
+// As DevToolsNetLogObserver shares live data with objects that live on the
+// IO Thread, it must also reside on the IO Thread.  Only OnAddEntry can be
+// called from other threads.
+class DevToolsNetLogObserver: public ChromeNetLog::ThreadSafeObserver {
   typedef webkit_glue::ResourceDevToolsInfo ResourceInfo;
 
  public:
-  // Observer implementation:
+  // ThreadSafeObserver implementation:
   virtual void OnAddEntry(net::NetLog::EventType type,
                           const base::TimeTicks& time,
                           const net::NetLog::Source& source,
                           net::NetLog::EventPhase phase,
                           net::NetLog::EventParameters* params);
 
   static void Attach(IOThread* thread);
   static void Detach();
 
   // Must be called on the IO thread. May return NULL if no observers
@@ skipping 12 matching lines @@
 
   ResourceInfo* GetResourceInfo(uint32 id);
 
   ChromeNetLog* chrome_net_log_;
   RequestToInfoMap request_to_info_;
 
   DISALLOW_COPY_AND_ASSIGN(DevToolsNetLogObserver);
 };
 
 #endif  // CHROME_BROWSER_DEBUGGER_DEVTOOLS_NETLOG_OBSERVER_H_