Test <img crossorigin> handling of 401 responses.

Test <img crossorigin> handling of 401 responses.

A CORS-enabled fetch to a resource that isn't CORS enabled, but returns a
401 should fail without offering up a UA dialog to supply credentials.

Blink already implements this; add test coverage over <img>.

R=
BUG=239918
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179834

[sof, 2014-08-08 12:25:36]

Please take a look.

The behavior that the associated bug requests has already been implemented by
various changes and improvements to CORS over the past year. Add a test to
provide coverage.

[Mike West, 2014-08-08 13:03:08]

LGTM, thanks for adding these tests.

[Mike West, 2014-08-08 13:03:11]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2014-08-08 13:03:41]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/sigbjornf@opera.com/450263002/1

[commit-bot: I haz the power, 2014-08-08 14:35:57]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_blink_compile_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_compile_dbg/bu...)

[commit-bot: I haz the power, 2014-08-08 14:44:46]

Change committed as 179834