[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/binding_access_checker_unittest.cc

 // 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.
 
-#include "extensions/renderer/binding_access_checker.h"
+#include "extensions/renderer/bindings/binding_access_checker.h"
 
 #include "base/bind.h"
-#include "extensions/renderer/api_binding_test.h"
+#include "extensions/renderer/bindings/api_binding_test.h"
 #include "gin/converter.h"
 
 namespace extensions {
 
 namespace {
 
 bool IsAvailable(v8::Local<v8::Context> context, const std::string& full_name) {
   EXPECT_TRUE(full_name == "available" || full_name == "unavailable")
       << full_name;
   return full_name == "available";
@@ skipping 28 matching lines @@
   {
     v8::TryCatch try_catch(isolate());
     EXPECT_FALSE(checker.HasAccessOrThrowError(context, "unavailable"));
     ASSERT_TRUE(try_catch.HasCaught());
     EXPECT_EQ("Uncaught Error: 'unavailable' is not available in this context.",
               gin::V8ToString(try_catch.Message()->Get()));
   }
 }
 
 }  // namespace extensions