[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/api_request_handler_unittest.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_request_handler.h"
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/optional.h"
 #include "base/strings/stringprintf.h"
 #include "base/values.h"
-#include "extensions/renderer/api_binding_test.h"
-#include "extensions/renderer/api_binding_test_util.h"
+#include "extensions/renderer/bindings/api_binding_test.h"
+#include "extensions/renderer/bindings/api_binding_test_util.h"
+#include "extensions/renderer/bindings/api_request_handler.h"
 #include "gin/converter.h"
 #include "gin/function_template.h"
 #include "gin/public/context_holder.h"
 #include "gin/public/isolate_holder.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "third_party/WebKit/public/web/WebScopedUserGesture.h"
 #include "third_party/WebKit/public/web/WebUserGestureIndicator.h"
 
 namespace extensions {
 
@@ skipping 456 matching lines @@
                                   std::string());
 
   EXPECT_EQ(ReplaceSingleQuotes(kArguments),
             GetStringPropertyFromObject(context->Global(), context, "result"));
 
   EXPECT_TRUE(request_handler.GetPendingRequestIdsForTesting().empty());
   EXPECT_FALSE(dispatched_request);
 }
 
 }  // namespace extensions