Don't DCHECK() on unknown types being asked from Wallet addresses.

R=estade@chromium.org
BUG=317837

Review URL: https://codereview.chromium.org/98493007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238907 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238907