Mark NewTabUITest.NTPHasThumbnails FLAKY.
Mark NewTabUITest.NTPHasThumbnails FLAKY.

BUG=http://crbug.com/51721
TEST=ui_tests

Review URL: http://codereview.chromium.org/3169003

git-svn-id: http://src.chromium.org/svn/trunk/src@55624 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 9aa800fa5e075d60cb92e770dd37f6796d576437
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser