[Extensions Bindings] Request JS execution from messaging bindings

extensions/renderer/native_extension_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/native_extension_bindings_system.h"
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "content/public/common/console_message_level.h"
 #include "content/public/common/content_switches.h"
@@ skipping 470 matching lines @@
     ScriptContext* context) {
   v8::HandleScope handle_scope(context->isolate());
   v8::Context::Scope context_scope(context->v8_context());
   EventFilteringInfo filter;
   if (filtering_info_dict)
     filter = EventFilteringInfo(*filtering_info_dict);
   api_system_.FireEventInContext(event_name, context->v8_context(), *event_args,
                                  filter);
 }
 
+bool NativeExtensionBindingsSystem::HasEventListenerInContext(
+    const std::string& event_name,
+    ScriptContext* context) {
+  v8::HandleScope handle_scope(context->isolate());
+  return api_system_.event_handler()->HasListenerForEvent(
+      event_name, context->v8_context());
+}
+
 void NativeExtensionBindingsSystem::HandleResponse(
     int request_id,
     bool success,
     const base::ListValue& response,
     const std::string& error) {
   // Some API calls result in failure, but don't set an error. Use a generic and
   // unhelpful error string.
   // TODO(devlin): Track these down and fix them. See crbug.com/648275.
   api_system_.CompleteRequest(
       request_id, response,
@@ skipping 184 matching lines @@
     v8::Local<v8::Value>* binding_util_out) {
   gin::Handle<APIBindingJSUtil> handle = gin::CreateHandle(
       context->GetIsolate(),
       new APIBindingJSUtil(
           api_system_.type_reference_map(), api_system_.request_handler(),
           api_system_.event_handler(), base::Bind(&CallJsFunction)));
   *binding_util_out = handle.ToV8();
 }
 
 }  // namespace extensions