[Extensions] Simplify EventFilteringInfo

extensions/common/event_matcher.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_MATCHER_H_
 #define EXTENSIONS_COMMON_EVENT_MATCHER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/values.h"
 
 namespace extensions {
-
-class EventFilteringInfo;
+struct EventFilteringInfo;
 
 extern const char kEventFilterServiceTypeKey[];
 
 // Matches EventFilteringInfos against a set of criteria. This is intended to
 // be used by EventFilter which performs efficient URL matching across
 // potentially many EventMatchers itself. This is why this class only exposes
 // MatchNonURLCriteria() - URL matching is handled by EventFilter.
 class EventMatcher {
  public:
   EventMatcher(std::unique_ptr<base::DictionaryValue> filter, int routing_id);
@@ skipping 32 matching lines @@
   const std::unique_ptr<base::DictionaryValue> filter_;
 
   const int routing_id_;
 
   DISALLOW_COPY_AND_ASSIGN(EventMatcher);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_EVENT_MATCHER_H_