Revert "GTTF: refactor interface..." and Revert "GTTF: Implement test retries."

Speculative revert in attempt to fix "XP Tests (1)" failures from build #28642: http://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29
I will revert this revert if this doesn't resolve the problem.

TBR=phajdan.jr@chromium.org

Review URL: https://codereview.chromium.org/28103004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230375 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230375