Update NetLog to be thread safe.

chrome/browser/net/load_timing_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_NET_LOAD_TIMING_OBSERVER_H_
 #define CHROME_BROWSER_NET_LOAD_TIMING_OBSERVER_H_
 #pragma once
 
 #include "base/gtest_prod_util.h"
 #include "base/hash_tables.h"
 #include "base/time.h"
 #include "chrome/browser/net/chrome_net_log.h"
 #include "net/base/net_log.h"
 #include "webkit/glue/resource_loader_bridge.h"
 
 class URLRequest;
 struct ResourceResponse;
 
 // LoadTimingObserver watches the NetLog event stream and collects the network
 // timing information.
-class LoadTimingObserver : public ChromeNetLog::Observer {
+//
+// LoadTimingObserver lives completely on the IOThread and ignores events from
+// other threads.  It is not safe to use from other threads.
+class LoadTimingObserver : public ChromeNetLog::ThreadSafeObserver {
  public:
   struct URLRequestRecord {
     URLRequestRecord();
 
     webkit_glue::ResourceLoadTimingInfo timing;
     uint32 connect_job_id;
     uint32 socket_log_id;
     bool socket_reused;
     base::TimeTicks base_ticks;
   };
 
   struct ConnectJobRecord {
     base::TimeTicks dns_start;
     base::TimeTicks dns_end;
   };
 
   struct SocketRecord {
     base::TimeTicks ssl_start;
     base::TimeTicks ssl_end;
   };
 
   LoadTimingObserver();
   ~LoadTimingObserver();
 
   URLRequestRecord* GetURLRequestRecord(uint32 source_id);
 
-  // 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 PopulateTimingInfo(URLRequest* request,
                                  ResourceResponse* response);
 
  private:
@@ skipping 29 matching lines @@
   URLRequestToRecordMap url_request_to_record_;
   ConnectJobToRecordMap connect_job_to_record_;
   SocketToRecordMap socket_to_record_;
   uint32 last_connect_job_id_;
   ConnectJobRecord last_connect_job_record_;
 
   DISALLOW_COPY_AND_ASSIGN(LoadTimingObserver);
 };
 
 #endif  // CHROME_BROWSER_NET_LOAD_TIMING_OBSERVER_H_