Fix a race in the ChromeFrame metrics service start up code. This race could ...

chrome_frame/metrics_service.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.
 
 // This file defines a service that collects information about the user
 // experience in order to help improve future versions of the app.
 
 #ifndef CHROME_FRAME_METRICS_METRICS_SERVICE_H_
 #define CHROME_FRAME_METRICS_METRICS_SERVICE_H_
 
 #include <map>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/lazy_instance.h"
+#include "base/lock.h"
 #include "base/metrics/histogram.h"
 #include "base/platform_thread.h"
 #include "base/scoped_ptr.h"
 #include "base/thread_local.h"
 #include "chrome/common/metrics_helpers.h"
 
 // TODO(ananta)
 // Refactor more common code from chrome/browser/metrics/metrics_service.h into
 // the MetricsServiceBase class.
 class MetricsService : public MetricsServiceBase {
@@ skipping 113 matching lines @@
   int session_id_;
 
   PlatformThreadId thread_;
 
   // Indicates if this is the first uma upload from this instance.
   bool initial_uma_upload_;
 
   // The transmission timer id returned by SetTimer
   int transmission_timer_id_;
 
+  // Used to serialize the Start and Stop operations on the metrics service.
+  static Lock metrics_service_lock_;
+
   DISALLOW_COPY_AND_ASSIGN(MetricsService);
 };
 
 #endif  // CHROME_FRAME_METRICS_METRICS_SERVICE_H_
-