Mac App Launcher is positioned on center of dock in certain cases.

The app launcher will be positioned on the center of the dock if the
cursor is not visible (previously would be in the lower-left corner) or
too far away from the dock (previously would be aligned with the cursor).

BUG=312851

Review URL: https://codereview.chromium.org/93863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238528 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238528
Docserver: Include <h4> tags in the table of contents, it's needed for the API
reference. Note that until the whole of bug 325555 is fixed the API reference
will still look wonky, and in fact this makes it look even wonkier.

BUG=325555
R=yoz@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/103413002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238529 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238529