Create an API around UtilityProcessHost and use that from chrome.

content/public/browser/utility_process_host.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_PUBLIC_BROWSER_UTILITY_PROCESS_HOST_H_
+#define CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_HOST_H_
+#pragma once
+
+#include "base/process_util.h"
+#include "content/common/content_export.h"
+#include "content/public/browser/browser_thread.h"
+#include "ipc/ipc_message.h"
+
+class FilePath;
+
+namespace content {
+
+class UtilityProcessHostClient;
+
+// This class acts as the browser-side host to a utility child process.  A
+// utility process is a short-lived process that is created to run a specific
+// task.  This class lives solely on the IO thread.
+// If you need a single method call in the process, use StartFooBar(p).
+// If you need multiple batches of work to be done in the process, use
+// StartBatchMode(), then multiple calls to StartFooBar(p), then finish with
+// EndBatchMode().
+//
+// Note: If your class keeps a ptr to an object of this type, grab a weak ptr to
+// avoid a use after free since this object is deleted synchronously but the
+// client notification is asynchronous.  See http://crbug.com/108871.
+class UtilityProcessHost : public IPC::Message::Sender,
+                           public base::SupportsWeakPtr<UtilityProcessHost> {
+ public:
+  // Used to create a utility process.
+  static CONTENT_EXPORT UtilityProcessHost* Create(
+      UtilityProcessHostClient* client,
+      BrowserThread::ID client_thread_id);
+
+  virtual ~UtilityProcessHost() {}
+
+  // Starts utility process in batch mode. Caller must call EndBatchMode()
+  // to finish the utility process.
+  virtual bool StartBatchMode() = 0;
+
+  // Ends the utility process. Must be called after StartBatchMode().
+  virtual void EndBatchMode() = 0;
+
+  // Allows a directory to be opened through the sandbox, in case it's needed by
+  // the operation.
+  virtual void SetExposedDir(const FilePath& dir) = 0;
+
+  // Make the process run without a sandbox.
+  virtual void DisableSandbox() = 0;
+
+  // If the sandbox is being used and we are on Linux, launch the process from
+  // the zygote. Can only be used for tasks that do not require FS access.
+  virtual void EnableZygote() = 0;
+
+#if defined(OS_POSIX)
+  virtual void SetEnv(const base::environment_vector& env) = 0;
+#endif
+};
+
+};  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_HOST_H_