[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/binding_access_checker.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 "base/strings/stringprintf.h"
-#include "gin/converter.h"
-
-namespace extensions {
-
-BindingAccessChecker::BindingAccessChecker(
-    const AvailabilityCallback& is_available)
-    : is_available_(is_available) {}
-BindingAccessChecker::~BindingAccessChecker() {}
-
-bool BindingAccessChecker::HasAccess(v8::Local<v8::Context> context,
-                                     const std::string& full_name) const {
-  return is_available_.Run(context, full_name);
-}
-
-bool BindingAccessChecker::HasAccessOrThrowError(
-    v8::Local<v8::Context> context,
-    const std::string& full_name) const {
-  if (!HasAccess(context, full_name)) {
-    context->GetIsolate()->ThrowException(v8::Exception::Error(gin::StringToV8(
-        context->GetIsolate(),
-        base::StringPrintf("'%s' is not available in this context.",
-                           full_name.c_str()))));
-    return false;
-  }
-
-  return true;
-}
-
-}  // namespace extensions