Views: Make it possible to flip the ok/cancel button order for dialogs.

BUG=339261

Review URL: https://codereview.chromium.org/148193003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249882 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249882