ServiceWorker: Release a reference when it fails to dispatch ExtendableMessageEvent

content/browser/message_port_service.cc

Index: content/browser/message_port_service.cc
diff --git a/content/browser/message_port_service.cc b/content/browser/message_port_service.cc
index 21fc76d40bc078cc216ce2525fe0b586d1903185..789e2aa36f2051e1db323ca9e2aa3602b030588a 100644
--- a/content/browser/message_port_service.cc
+++ b/content/browser/message_port_service.cc
@@ -295,6 +295,13 @@ void MessagePortService::HoldMessages(int message_port_id) {
   message_ports_[message_port_id].hold_messages_for_destination = true;
 }
 
+bool MessagePortService::AreMessagesHeld(int message_port_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (!message_ports_.count(message_port_id))
+    return false;
+  return message_ports_[message_port_id].hold_messages_for_destination;
+}
+
 void MessagePortService::ClosePort(int message_port_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (!message_ports_.count(message_port_id)) {