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This re-enables several tests that were disabled, and
adds new expectations where they were missing before.
It also cleans up some tests by suppressing unnecessary
attributes, and makes the Mac "subrole" attribute hidden
by default since it's rarely useful.

The correctness of the output was determined by these specs:

HTML: http://www.w3.org/TR/html-aapi/
ARIA: http://www.w3.org/WAI/PF/aria-implementation/

BUG=165838
TBR=dtseng


Review URL: https://chromiumcodereview.appspot.com/11785038

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175687 0039d316-1c4b-4281-b951-d872f2087c98