Fixed null dereference in GPU watchdog termination code....

chrome/gpu/gpu_watchdog_thread.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_GPU_GPU_WATCHDOG_THREAD_H_
 #define CHROME_GPU_GPU_WATCHDOG_THREAD_H_
 
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
 #include "base/task.h"
 #include "base/thread.h"
 
 // A thread that intermitently sends tasks to a group of watched message loops
 // and deliberately crashes if one of them does not respond after a timeout.
 class GpuWatchdogThread : public base::Thread,
                           public base::RefCountedThreadSafe<GpuWatchdogThread> {
  public:
-  GpuWatchdogThread(MessageLoop* watched_message_loop, int timeout);
+  explicit GpuWatchdogThread(int timeout);
   virtual ~GpuWatchdogThread();
 
   // Accessible on watched thread but only modified by watchdog thread.
   bool armed() const { return armed_; }
   void PostAcknowledge();
 
  protected:
   virtual void Init();
   virtual void CleanUp();
 
@@ skipping 13 matching lines @@
    private:
     void CheckArmed();
     GpuWatchdogThread* watchdog_;
   };
 
   void OnAcknowledge();
   void OnCheck();
   void OnExit();
   void Disable();
 
+  int64 GetWatchedThreadTime();
+
   MessageLoop* watched_message_loop_;
   int timeout_;
   volatile bool armed_;
   GpuWatchdogTaskObserver task_observer_;
 
+#if defined(OS_WIN)
+  void* watched_thread_handle_;
+  int64 arm_time_;
+#endif
+
   typedef ScopedRunnableMethodFactory<GpuWatchdogThread> MethodFactory;
   scoped_ptr<MethodFactory> method_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuWatchdogThread);
 };
 
 #endif  // CHROME_GPU_GPU_WATCHDOG_THREAD_H_