Fix "unreachable code" warnings (MSVC warning 4702) in ui/.

BUG=346399
TEST=none
R=sky@chromium.org

Review URL: https://codereview.chromium.org/202173005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257745 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed