Check default_container in FramePainter::UseSoloWindowHeader

I happened to catch this while debugging.

BUG=120786
TEST=Crash does not show up (hard to repro)


Review URL: http://codereview.chromium.org/9854045

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@129591 0039d316-1c4b-4281-b951-d872f2087c98