Bug fix: Translate New UX: Stop consuming an Enter/Space key event when the combobox's style is not STYLE_NOTIFY_ON_CLICK.

BUG=329995
TEST=views_unittests --gtest_filter=ComboboxTest.*

Review URL: https://codereview.chromium.org/119853002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242517 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242517