added sync_unit_tests to mac/chromeos unit test builds.
added sync_unit_tests to mac/chromeos unit test builds.

BUG=32871
TEST=trybots

Review URL: http://codereview.chromium.org/1739014

git-svn-id: http://src.chromium.org/svn/trunk/src@46026 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 3acecf337a91eef0756cfc3b324002e12a38e6aa
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