Mark ErrorPageTest.IFrameDNSError_GoBackAndForward as flaky since it failed on Linux.
Mark ErrorPageTest.IFrameDNSError_GoBackAndForward as flaky since it failed
on Linux.

BUG=19361

Review URL: http://codereview.chromium.org/384050

git-svn-id: http://src.chromium.org/svn/trunk/src@31689 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: bec54ce2f45a4f23b5a16b2d78e5004e7f261e60
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