Fix race condition with message ports being dropped if sent before a worker starts.

BUG=22315
TEST=covered by worker-messageport-gc.html
Review URL: http://codereview.chromium.org/208045

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@26749 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 1 deletions

diff --git a/chrome/browser/worker_host/message_port_dispatcher.cc b/chrome/browser/worker_host/message_port_dispatcher.cc
index 41ebc37..c6e992d 100644
--- a/chrome/browser/worker_host/message_port_dispatcher.cc
+++ b/chrome/browser/worker_host/message_port_dispatcher.cc
@@ -193,8 +193,9 @@ void MessagePortDispatcher::OnQueueMessages(int message_port_id) {
   }
 
   MessagePort& port = message_ports_[message_port_id];
-  port.queue_messages = true;
   port.sender->Send(new WorkerProcessMsg_MessagesQueued(port.route_id));
+  port.queue_messages = true;
+  port.sender = NULL;
 }
 
 void MessagePortDispatcher::OnSendQueuedMessages(
@@ -212,6 +213,14 @@ void MessagePortDispatcher::OnSendQueuedMessages(
   port.queued_messages.insert(port.queued_messages.begin(),
                               queued_messages.begin(),
                               queued_messages.end());
+  SendQueuedMessagesIfPossible(message_port_id);
+}
+
+void MessagePortDispatcher::SendQueuedMessagesIfPossible(int message_port_id) {
+  MessagePort& port = message_ports_[message_port_id];
+  if (port.queue_messages || !port.sender)
+    return;
+
   for (QueuedMessages::iterator iter = port.queued_messages.begin();
        iter != port.queued_messages.end(); ++iter) {
     PostMessageTo(message_port_id, iter->first, iter->second);