[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/api_request_handler.h

 // Copyright 2016 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 EXTENSIONS_RENDERER_API_REQUEST_HANDLER_H_
-#define EXTENSIONS_RENDERER_API_REQUEST_HANDLER_H_
+#ifndef EXTENSIONS_RENDERER_BINDINGS_API_REQUEST_HANDLER_H_
+#define EXTENSIONS_RENDERER_BINDINGS_API_REQUEST_HANDLER_H_
 
 #include <map>
 #include <memory>
 #include <set>
 
 #include "base/callback.h"
 #include "base/macros.h"
-#include "extensions/renderer/api_binding_types.h"
-#include "extensions/renderer/api_last_error.h"
+#include "extensions/renderer/bindings/api_binding_types.h"
+#include "extensions/renderer/bindings/api_last_error.h"
 #include "third_party/WebKit/public/web/WebUserGestureToken.h"
 #include "v8/include/v8.h"
 
 namespace base {
 class ListValue;
 }
 
 namespace extensions {
 
 // A wrapper around a map for extension API calls. Contains all pending requests
@@ skipping 93 matching lines @@
   // (where we have to deal with e.g. blocking javascript).
   CallJSFunction call_js_;
 
   APILastError last_error_;
 
   DISALLOW_COPY_AND_ASSIGN(APIRequestHandler);
 };
 
 }  // namespace extensions
 
-#endif  // EXTENSIONS_RENDERER_API_REQUEST_HANDLER_H_
+#endif  // EXTENSIONS_RENDERER_BINDINGS_API_REQUEST_HANDLER_H_