[Extensions] Use a separate IPC message for extension events

extensions/common/event_filtering_info.h

 // 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.
 
 #ifndef EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_
 #define EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_
 
 #include <memory>
 
 #include "url/gurl.h"
 
 namespace base {
-class Value;
+class DictionaryValue;
 }
 
 namespace extensions {
 
 // Extra information about an event that is used in event filtering.
 //
 // This is the information that is matched against criteria specified in JS
 // extension event listeners. Eg:
 //
 // chrome.someApi.onSomeEvent.addListener(cb,
@@ skipping 29 matching lines @@
 
   bool has_url() const { return has_url_; }
   const GURL& url() const { return url_; }
 
   bool has_instance_id() const { return has_instance_id_; }
   int instance_id() const { return instance_id_; }
 
   bool has_service_type() const { return !service_type_.empty(); }
   const std::string& service_type() const { return service_type_; }
 
-  std::unique_ptr<base::Value> AsValue() const;
-  bool IsEmpty() const;
+  std::unique_ptr<base::DictionaryValue> AsValue() const;
 
  private:
   bool has_url_;
   GURL url_;
   std::string service_type_;
 
   bool has_instance_id_;
   int instance_id_;
 
   bool has_window_type_;
   std::string window_type_;
 
   bool has_window_exposed_by_default_;
   bool window_exposed_by_default_;
 
   // Allow implicit copy and assignment.
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_