[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/argument_spec.h

Index: extensions/renderer/bindings/argument_spec.h
diff --git a/extensions/renderer/argument_spec.h b/extensions/renderer/bindings/argument_spec.h
similarity index 97%
rename from extensions/renderer/argument_spec.h
rename to extensions/renderer/bindings/argument_spec.h
index 0d517731342668a2d2e960cb61cc491aa527bc62..4425568da1ad2d0024914a54b1ef0fc9ea00fdf9 100644
--- a/extensions/renderer/argument_spec.h
+++ b/extensions/renderer/bindings/argument_spec.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef EXTENSIONS_RENDERER_ARGUMENT_SPEC_H_
-#define EXTENSIONS_RENDERER_ARGUMENT_SPEC_H_
+#ifndef EXTENSIONS_RENDERER_BINDINGS_ARGUMENT_SPEC_H_
+#define EXTENSIONS_RENDERER_BINDINGS_ARGUMENT_SPEC_H_
 
 #include <map>
 #include <memory>
@@ -179,4 +179,4 @@ class ArgumentSpec {
 
 }  // namespace extensions
 
-#endif  // EXTENSIONS_RENDERER_ARGUMENT_SPEC_H_
+#endif  // EXTENSIONS_RENDERER_BINDINGS_ARGUMENT_SPEC_H_