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

native_client_sdk/src/libraries/ppapi_simple/ps.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 PPAPI_SIMPLE_PS_H_
 #define PPAPI_SIMPLE_PS_H_
 
 #include "ppapi/c/pp_instance.h"
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 EXTERN_C_BEGIN
 
 /**
  * The ppapi_simple library simplifies the use of the Pepper interfaces by
  * providing a more traditional 'C' or 'C++' style framework.  The library
  * creates an PSInstance derived object based on the ppapi_cpp library and
  * initializes the nacl_io library to provide a POSIX friendly I/O environment.
  *
  * In order to provide a standard blocking environment, the library will hide
@@ skipping 84 matching lines @@
 void* PSUserCreateInstance(PP_Instance inst) {                     \
   PPAPI_SIMPLE_DECLARE_PARAMS(params, ##__VA_ARGS__, NULL, NULL)   \
   return (void *) new classname(inst, params);                     \
 }
 
 EXTERN_C_END
 
 
 #endif  // PPAPI_SIMPLE_PPAPI_SIMPLE_H