[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/event_emitter_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/event_emitter.h"
+#include "extensions/renderer/bindings/event_emitter.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
-#include "extensions/renderer/api_binding_test.h"
-#include "extensions/renderer/api_binding_test_util.h"
-#include "extensions/renderer/api_event_listeners.h"
+#include "extensions/renderer/bindings/api_binding_test.h"
+#include "extensions/renderer/bindings/api_binding_test_util.h"
+#include "extensions/renderer/bindings/api_event_listeners.h"
 #include "gin/handle.h"
 
 namespace extensions {
 namespace {
 
 void DoNothingOnListenerChange(binding::EventListenersChanged changed,
                                const base::DictionaryValue* filter,
                                bool was_manual,
                                v8::Local<v8::Context> context) {}
 
@@ skipping 87 matching lines @@
   for (const char* property :
        {"eventArgs1", "eventArgs2", "eventArgs3", "eventArgs4"}) {
     EXPECT_EQ(kExpectedEventArgs, GetStringPropertyFromObject(
                                       context->Global(), context, property));
   }
   EXPECT_EQ("{\"results\":[\"listener1\",{\"listener\":\"listener2\"}]}",
             V8ToString(dispatch_result, context));
 }
 
 }  // namespace extensions