GitLab

This CL addresses the a11y issue that the Terms of Service screen does
not have any focused control by default. The focus is now placed on the
back button by default and shifts to the accept button when the Terms of
Service have finished loading.

BUG=175730
TEST=Manual


Review URL: https://chromiumcodereview.appspot.com/12221143

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182096 0039d316-1c4b-4281-b951-d872f2087c98