extensions: Destroy ExtensionMessageFilter on IO thread.

extensions/browser/extension_message_filter.cc

Index: extensions/browser/extension_message_filter.cc
diff --git a/extensions/browser/extension_message_filter.cc b/extensions/browser/extension_message_filter.cc
index e25480dcaf54317d778d4c3e369267d1c4d89f84..bffc936ce956430a03fe04612bd8bd57118ac66c 100644
--- a/extensions/browser/extension_message_filter.cc
+++ b/extensions/browser/extension_message_filter.cc
@@ -53,6 +53,10 @@ void ExtensionMessageFilter::OverrideThreadForMessage(
   }
 }
 
+void ExtensionMessageFilter::OnDestruct() const {
+  BrowserThread::DeleteOnIOThread::Destruct(this);

[James Cook, 2014/06/02 19:50:43]

I would document either here or in the header why it has to be destroyed on the
IO thread.

Optional alternative: If you think we're slathering this with too many comments
to cover up a code smell, consider splitting into two message filters, one that
just handles IO thread messages.

[Daniel Erat, 2014/06/02 20:07:59]

Done.

(i went with the easy/lazy approach of adding comments)

+}
+
 bool ExtensionMessageFilter::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(ExtensionMessageFilter, message)