Enable global command test on linux gtk.

BUG=302437
TEST=interactive_ui_tests --gtest_filter=GlobalCommandsApiTest.GlobalCommand

Review URL: https://codereview.chromium.org/28463002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229805 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229805