This would be consistent with the network path which uses UTF8Encoding when uploading text data.
Created attachment 290311 [details] Patch
Comment on attachment 290311 [details] Patch Attachment 290311 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.webkit.org/results/2174077 New failing tests: fast/images/pixel-crack-image-background-webkit-transform-scale.html
Created attachment 290321 [details] Archive of layout-test-results from ews106 for mac-yosemite-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: ews106 Port: mac-yosemite-wk2 Platform: Mac OS X 10.10.5
Comment on attachment 290311 [details] Patch Clearing flags on attachment: 290311 Committed r206636: <http://trac.webkit.org/changeset/206636>
All reviewed patches have been landed. Closing bug.