Move thread_pool.h into utils so it can be shared by more than one example.

native_client_sdk/src/libraries/sdk_util/auto_lock.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 LIBRARIES_UTILS_AUTO_LOCK_H_
-#define LIBRARIES_UTILS_AUTO_LOCK_H_
+#ifndef LIBRARIES_SDK_UTIL_AUTO_LOCK_H_
+#define LIBRARIES_SDK_UTIL_AUTO_LOCK_H_
 
 #include <pthread.h>
 
 class AutoLock {
  public:
   explicit AutoLock(pthread_mutex_t* lock) {
     lock_ = lock;
     pthread_mutex_lock(lock_);
   }
   ~AutoLock() {
     if (lock_) pthread_mutex_unlock(lock_);
   }
 
   void Unlock() {
     if (lock_) pthread_mutex_unlock(lock_);
     lock_ = NULL;
   }
 
  private:
   pthread_mutex_t* lock_;
 };
 
-#endif  // LIBRARIES_UTILS_AUTO_LOCK_H_
+#endif  // LIBRARIES_SDK_UTIL_AUTO_LOCK_H_
+