Makes InfolistWindow as a BubbleDelegateView.

Now Offscreen repositioning logic can be done as a standard bubble.
It has a special BubbleBorder to align the infolist window with
the candidate window.

BUG=325813
R=nona@chromium.org, komatsu@chromium.org
TEST=manually

Review URL: https://codereview.chromium.org/101863009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242613 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242613