Mark PreferPreviousSearch as flaky on ChromeOS.
Mark PreferPreviousSearch as flaky on ChromeOS.

BUG=32312
TBR=jshin
TEST=NONE

Review URL: http://codereview.chromium.org/550052

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@36306 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser