Add a new GetInstance() method for singleton classes used in chrome/browser files.

chrome/browser/renderer_host/render_sandbox_host_linux.h

 // Copyright (c) 2009 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.
 
 // http://code.google.com/p/chromium/wiki/LinuxSandboxIPC
 
 #ifndef CHROME_BROWSER_RENDERER_HOST_RENDER_SANDBOX_HOST_LINUX_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_SANDBOX_HOST_LINUX_H_
 #pragma once
 
 #include <string>
 
 #include "base/logging.h"
-#include "base/singleton.h"
+
+template <typename T> struct DefaultSingletonTraits;
 
 // This is a singleton object which handles sandbox requests from the
 // renderers.
 class 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(const std::string& sandbox_path);
 
  private:
   friend struct DefaultSingletonTraits<RenderSandboxHostLinux>;
   // This object must be constructed on the main thread.
   RenderSandboxHostLinux();
   ~RenderSandboxHostLinux();
 
   // Whether Init() has been called yet.
   bool initialized_;
 
   int renderer_socket_;
   int childs_lifeline_fd_;
   pid_t pid_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderSandboxHostLinux);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_SANDBOX_HOST_LINUX_H_