Extend EventFilter to handle the case where EventMatchers from event X get

chrome/common/extensions/event_filtering_info.h

Index: chrome/common/extensions/event_filtering_info.h
diff --git a/chrome/common/extensions/event_filtering_info.h b/chrome/common/extensions/event_filtering_info.h
index e7077f1ba89bb213946d9a06349befbd6819a970..89d4d32f008dac667c6d1f03c24eac21005162dd 100644
--- a/chrome/common/extensions/event_filtering_info.h
+++ b/chrome/common/extensions/event_filtering_info.h
@@ -27,11 +27,13 @@ class EventFilteringInfo {
   bool has_url() const { return has_url_; }
   const GURL& url() const { return url_; }
 
+  std::string AsJSONString() const;
+
  private:
   bool has_url_;
   GURL url_;
 
-  DISALLOW_COPY_AND_ASSIGN(EventFilteringInfo);
+  // Allow implicit copy and assignment.
 };
 
 }  // namespace extensions