[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/binding_access_checker.h

 // Copyright 2017 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_BINDING_ACCESS_CHECKER_H_
-#define EXTENSIONS_RENDERER_BINDING_ACCESS_CHECKER_H_
+#ifndef EXTENSIONS_RENDERER_BINDINGS_BINDING_ACCESS_CHECKER_H_
+#define EXTENSIONS_RENDERER_BINDINGS_BINDING_ACCESS_CHECKER_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "v8/include/v8.h"
 
 namespace extensions {
 
 // A helper class to handle access-checking API features.
@@ skipping 18 matching lines @@
                              const std::string& full_name) const;
 
  private:
   AvailabilityCallback is_available_;
 
   DISALLOW_COPY_AND_ASSIGN(BindingAccessChecker);
 };
 
 }  // namespace extensions
 
-#endif  // EXTENSIONS_RENDERER_BINDING_ACCESS_CHECKER_H_
+#endif  // EXTENSIONS_RENDERER_BINDINGS_BINDING_ACCESS_CHECKER_H_