Make SandboxIPCProcess a thread.

content/browser/renderer_host/render_sandbox_host_linux.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_RENDERER_HOST_RENDER_SANDBOX_HOST_LINUX_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_SANDBOX_HOST_LINUX_H_
 
 #include <string>
 
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/simple_thread.h"
+#include "content/browser/renderer_host/sandbox_ipc_linux.h"
 #include "content/common/content_export.h"
 
 template <typename T> struct DefaultSingletonTraits;
 
 namespace content {
 
 // This is a singleton object which handles sandbox requests from the
 // renderers.
 class CONTENT_EXPORT RenderSandboxHostLinux {
  public:
   // Returns the singleton instance.
   static RenderSandboxHostLinux* GetInstance();
 
   // Get the file descriptor which renderers should be given in order to signal
   // crashes to the browser.
   int GetRendererSocket() const {
     DCHECK(initialized_);
     return renderer_socket_;
   }
-  pid_t pid() const {
-    DCHECK(initialized_);
-    return pid_;
-  }
   void Init();
 
  private:
   friend struct DefaultSingletonTraits<RenderSandboxHostLinux>;
   // This object must be constructed on the main thread.
   RenderSandboxHostLinux();
   ~RenderSandboxHostLinux();
 
   bool ShutdownIPCChannel();
 
   // Whether Init() has been called yet.
   bool initialized_;
 
   int renderer_socket_;
   int childs_lifeline_fd_;
-  pid_t pid_;
+
+  scoped_ptr<SandboxIPCHandler> ipc_handler_;
+  scoped_ptr<base::DelegateSimpleThread> ipc_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderSandboxHostLinux);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_SANDBOX_HOST_LINUX_H_