Created a new process type called the service process to host background task...

chrome/service/service_process.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_SERVICE_SERVICE_PROCESS_H_
+#define CHROME_SERVICE_SERVICE_PROCESS_H_
+
+
+#include "base/thread.h"
+
+class CloudPrintProxy;
+
+// The ServiceProcess does not inherit from ChildProcess because this
+// process can live independently of the browser process.
+class ServiceProcess {
+ public:
+  ServiceProcess();
+  ~ServiceProcess();
+
+  bool Initialize();
+  bool Teardown();
+  // TODO(sanjeevr): Change various parts of the code such as
+  // net::ProxyService::CreateSystemProxyConfigService to take in
+  // MessageLoopProxy* instead of MessageLoop*. When we have done that, we can
+  // remove the io_thread() and file_thread() accessors and replace them with
+  // io_message_loop_proxy() and file_message_loop_proxy() respectively.
+
+  // Returns the thread that we perform I/O coordination on (network requests,
+  // communication with renderers, etc.
+  // NOTE: You should ONLY use this to pass to IPC or other objects which must
+  // need a MessageLoop*. If you just want to post a task, use the thread's
+  // message_loop_proxy() as it takes care of checking that a thread is still
+  // alive, race conditions, lifetime differences etc.
+  // If you still must use this, need to check the return value for NULL.
+  base::Thread* io_thread() const {
+    return io_thread_.get();
+  }
+  // Returns the thread that we perform random file operations on. For code
+  // that wants to do I/O operations (not network requests or even file: URL
+  // requests), this is the thread to use to avoid blocking the UI thread.
+  base::Thread* file_thread() const {
+    return file_thread_.get();
+  }
+  CloudPrintProxy* cloud_print_proxy();
+
+ private:
+  scoped_ptr<base::Thread> io_thread_;
+  scoped_ptr<base::Thread> file_thread_;
+  scoped_ptr<CloudPrintProxy> cloud_print_proxy_;
+
+  DISALLOW_COPY_AND_ASSIGN(ServiceProcess);
+};
+
+extern ServiceProcess* g_service_process;
+
+#endif  // CHROME_SERVICE_SERVICE_PROCESS_H_
+