Regression(r119759): Heap-use-after-free in webkit_glue::WebURLLoaderImpl::Context::OnReceivedResponse
https://bugs.webkit.org/show_bug.cgi?id=103563

A subresource could receive a body on a 404 if its call to CachedResource::error() resulted in a nested message loop.
That caused a crash when data was received, as the Subresource was in the Finished state already. Now when receiving
data we ignore these bodies, avoiding the crash.

Reviewed by Nate Chapin.

No new tests in WebKit, since it required a nested message loop which isn't present in chromium DumpRender tree.
There's a Chrome side browser test, see https://codereview.chromium.org/11778083/

* loader/SubresourceLoader.cpp:
(WebCore::SubresourceLoader::checkForHTTPStatusCodeError):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@139551 268f45cc-cd09-0410-ab3c-d52691b4dbfc