[Mojo] Move JS bindings out of public

mojo/apps/js/bindings/threading.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_APPS_JS_THREADING_H_
 #define MOJO_APPS_JS_THREADING_H_
 
 #include "mojo/public/system/core.h"
 #include "v8/include/v8.h"
 
 namespace mojo {
 namespace apps {
 
 class Threading {
  public:
   static const char kModuleName[];
   static v8::Local<v8::ObjectTemplate> GetTemplate(v8::Isolate* isolate);
 };
 
 }  // namespace apps
 }  // namespace mojo
 
 #endif  // MOJO_APPS_JS_THREADING_H_