Having them on the prototype broke some sites due to the fact that these DOM attributes are currently not configurable. Once we make them configurable, we can move XHR attributes back to the prototype.
Created attachment 233938 [details] Patch
I filed bug 134364 to track fixing the issue with configurable attributes on the prototype.
Comment on attachment 233938 [details] Patch r=me
Let's add a test that models the definProperty("responseType") thingy.
Comment on attachment 233938 [details] Patch Attachment 233938 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-queues.appspot.com/results/4723205071699968 New failing tests: media/W3C/video/networkState/networkState_during_loadstart.html
Created attachment 233941 [details] Archive of layout-test-results from webkit-ews-10 for mac-mountainlion-wk2 The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews. Bot: webkit-ews-10 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.5
Created attachment 233942 [details] Patch
Comment on attachment 233942 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=233942&action=review I did not review this patch for correctness. I noticed a minor issue in the ChangeLog entry. > Source/WebCore/ChangeLog:8 > + No new tests. Please update the ChangeLog entry to reflect that this patch includes the test LayoutTests/js/dom/xhr-prototype-define-property.html
Committed r170534: <http://trac.webkit.org/changeset/170534>
<rdar://problem/17444323>