Have mojo_shell run in its custom thread on android.

mojo/shell/task_runners.h

 // Copyright 2013 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 MOJO_SHELL_TASK_RUNNERS_H_
 #define MOJO_SHELL_TASK_RUNNERS_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/threading/thread.h"
 
 namespace base {
 class SequencedWorkerPool;
 }
 
 namespace mojo {
 namespace shell {
 
 // A context object that contains the common task runners for the shell's main
 // process.
 class TaskRunners {
  public:
-  explicit TaskRunners(base::SingleThreadTaskRunner* ui_runner);
+  explicit TaskRunners(base::SingleThreadTaskRunner* shell_runner);
   ~TaskRunners();
 
-  base::SingleThreadTaskRunner* ui_runner() const {
-    return ui_runner_.get();
+  base::SingleThreadTaskRunner* shell_runner() const {
+    return shell_runner_.get();
   }
 
   base::SingleThreadTaskRunner* io_runner() const {
     return io_thread_->message_loop_proxy();
   }
 
   base::SequencedWorkerPool* blocking_pool() const {
     return blocking_pool_.get();
   }
 
  private:
-  // TODO(beng): should this be named shell_runner_?
-  scoped_refptr<base::SingleThreadTaskRunner> ui_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> shell_runner_;
   scoped_ptr<base::Thread> io_thread_;
 
   scoped_refptr<base::SequencedWorkerPool> blocking_pool_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskRunners);
 };
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_TASK_RUNNERS_H_