[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/api_bindings_system.cc

 // 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.
 
-#include "extensions/renderer/api_bindings_system.h"
+#include "extensions/renderer/bindings/api_bindings_system.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
-#include "extensions/renderer/api_binding_hooks.h"
+#include "extensions/renderer/bindings/api_binding_hooks.h"
 
 namespace extensions {
 
 APIBindingsSystem::APIBindingsSystem(
     const binding::RunJSFunction& call_js,
     const binding::RunJSFunctionSync& call_js_sync,
     const GetAPISchemaMethod& get_api_schema,
     const BindingAccessChecker::AvailabilityCallback& is_available,
     const APIRequestHandler::SendRequestMethod& send_request,
     const APIEventHandler::EventListenersChangedMethod& event_listeners_changed,
@@ skipping 115 matching lines @@
     const std::string& property_name,
     const base::ListValue* property_values) {
   auto iter = custom_types_.find(type_name);
   DCHECK(iter != custom_types_.end()) << "Custom type not found: " << type_name;
   return iter->second.Run(isolate, property_name, property_values,
                           &request_handler_, &event_handler_,
                           &type_reference_map_, &access_checker_);
 }
 
 }  // namespace extensions