[Extensions] Use a separate IPC message for extension events

extensions/common/event_filtering_info.cc

 // Copyright (c) 2012 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/common/event_filtering_info.h"
 
 #include <utility>
 
 #include "base/json/json_writer.h"
+#include "base/memory/ptr_util.h"
 #include "base/values.h"
 
 namespace extensions {
 
 EventFilteringInfo::EventFilteringInfo()
     : has_url_(false),
       has_instance_id_(false),
       instance_id_(0),
       has_window_type_(false),
       has_window_exposed_by_default_(false) {}
@@ skipping 17 matching lines @@
 void EventFilteringInfo::SetURL(const GURL& url) {
   url_ = url;
   has_url_ = true;
 }
 
 void EventFilteringInfo::SetInstanceID(int instance_id) {
   instance_id_ = instance_id;
   has_instance_id_ = true;
 }
 
-std::unique_ptr<base::Value> EventFilteringInfo::AsValue() const {
-  if (IsEmpty())
-    return base::Value::CreateNullValue();
-
-  std::unique_ptr<base::DictionaryValue> result(new base::DictionaryValue);
+std::unique_ptr<base::DictionaryValue> EventFilteringInfo::AsValue() const {
+  auto result = base::MakeUnique<base::DictionaryValue>();
   if (has_url_)
     result->SetString("url", url_.spec());
 
   if (has_instance_id_)
     result->SetInteger("instanceId", instance_id_);
 
   if (!service_type_.empty())
     result->SetString("serviceType", service_type_);
 
   if (has_window_type_)
     result->SetString("windowType", window_type_);
 
   if (has_window_exposed_by_default_)
     result->SetBoolean("windowExposedByDefault", window_exposed_by_default_);
 
-  return std::move(result);
-}
-
-bool EventFilteringInfo::IsEmpty() const {
-  return !has_window_type_ && !has_url_ && service_type_.empty() &&
-         !has_instance_id_ && !has_window_exposed_by_default_;
+  return result;
 }
 
 }  // namespace extensions