Update views infobars to correctly layout with any of their labels empty.  This
might happen depending on the locale or with certain confirm infobar subclasses.
To make this slightly simpler to code, ConfirmInfoBar now creates |link_|
unconditionally instead of only when non-empty.

This also adjusts AfterTranslateInfoBar::ContentMinimumWidth() to correctly
handle the |autodetermined_source_language_| case, in which some of the controls
don't appear.

Finally, this tweaks the translate infobars so that buttons which appear after
all the other text/buttons are spaced out using kEndOfLabelSpacing instead of
kButtonInLabelSpacing.  This looks better as logically these buttons aren't part
of the preceding "sentence".

BUG=none
TEST=none
R=msw@chromium.org

Review URL: https://codereview.chromium.org/122523002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242744 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242744