Set up content in-process main threads via factory

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_
 
 #include "base/process/launch.h"
+#include "base/threading/thread.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_sender.h"
 
 namespace base {
 class FilePath;
 class SequencedTaskRunner;
 }
 
 namespace content {
 class UtilityProcessHostClient;
 struct ChildProcessData;
 
+typedef base::Thread* (*UtilityMainThreadFactoryFunction)(
+    const std::string& id);
+
 // 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
@@ skipping 28 matching lines @@
   // 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;
 
   // Returns information about the utility child process.
   virtual const ChildProcessData& GetData() = 0;
 
 #if defined(OS_POSIX)
   virtual void SetEnv(const base::EnvironmentVector& env) = 0;
 #endif
+
+  CONTENT_EXPORT static void RegisterUtilityMainThreadFactory(
+      UtilityMainThreadFactoryFunction create);
 };
 
 };  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_HOST_H_