Protect WebURLLoaderImpl::Context while receiving responses.

webkit/glue/weburlloader_impl.cc

Index: webkit/glue/weburlloader_impl.cc
diff --git a/webkit/glue/weburlloader_impl.cc b/webkit/glue/weburlloader_impl.cc
index 2145ce32586b8d9db3c5b915f00071ee48651043..b57798ac1fe69ffd7debdbd2e6a34415207cc860 100644
--- a/webkit/glue/weburlloader_impl.cc
+++ b/webkit/glue/weburlloader_impl.cc
@@ -651,6 +651,7 @@ void WebURLLoaderImpl::Context::OnReceivedResponse(
     }
   }
 
+  scoped_refptr<Context> protect(this);

[darin (slow to review), 2013/05/23 14:42:09]

This looks like it'll do the trick to me.  However, I'm not a big fan of
protect(this) patterns.  I usually try to find some way to avoid it if I can. 
Maybe the caller of OnReceivedResponse can retain a reference, etc.  (I need to
study the code more...)

[gavinp, 2013/05/28 16:25:35]

Certainly the caller could, but that would be a bigger change to the code. The
typical call path is ResourceDispatcher::OnReceivedResponse calls through the
ResourceLoaderBridge::Peer interface, which Context implements.

Context is refcounted, but ResourceLoaderBridge::Peer is not.

I've spent some time playing with it, and I'm more comfortable guarding here
than making the abstract class Refcounted. I'll make an upload that does that
for comparison if you like, in the meantime I'd welcome your opinion.

   client_->didReceiveResponse(loader_, response);
 
   // We may have been cancelled after didReceiveResponse, which would leave us