Re-land of http://codereview.chromium.org/6094009 with Mac build fix....

chrome/gpu/gpu_thread.h

Index: chrome/gpu/gpu_thread.h
===================================================================
--- chrome/gpu/gpu_thread.h	(revision 70681)
+++ chrome/gpu/gpu_thread.h	(working copy)
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "base/basictypes.h"
+#include "base/command_line.h"
 #include "base/scoped_ptr.h"
 #include "base/time.h"
 #include "build/build_config.h"
@@ -21,12 +22,15 @@
 struct ChannelHandle;
 }
 
+class GpuWatchdogThread;
+
 class GpuThread : public ChildThread {
  public:
-  GpuThread();
+  explicit GpuThread(const CommandLine& command_line);
   ~GpuThread();
 
   void Init(const base::Time& process_start_time);
+  void StopWatchdog();
 
   // Remove the channel for a particular renderer.
   void RemoveChannel(int renderer_id);
@@ -36,6 +40,7 @@
   virtual bool OnControlMessageReceived(const IPC::Message& msg);
 
   // Message handlers.
+  void OnInitialize();
   void OnEstablishChannel(int renderer_id);
   void OnCloseChannel(const IPC::ChannelHandle& channel_handle);
   void OnSynchronize();
@@ -53,6 +58,10 @@
   static void SetDxDiagnostics(GpuThread* thread, const DxDiagNode& node);
 #endif
 
+  CommandLine command_line_;
+  base::Time process_start_time_;
+  scoped_refptr<GpuWatchdogThread> watchdog_thread_;
+
   typedef base::hash_map<int, scoped_refptr<GpuChannel> > GpuChannelMap;
   GpuChannelMap gpu_channels_;