The didSendBodyData delegate exists starting with 10.6, we don't need to check at runtime, or even to keep the code.
Created attachment 133887 [details] proposed patch One piece of mystery code less in WebCore.
Comment on attachment 133887 [details] proposed patch Attachment 133887 [details] did not pass mac-ews (mac): Output: http://queues.webkit.org/results/12143115
Committed <http://trac.webkit.org/changeset/112162>.