Cleanup: Remove the browser_list.h stub file. Part 3/3.

All the includes to it were already updated.

BUG=None
TEST=None

R=avi@chromium.org

Review URL: http://codereview.chromium.org/6807001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@80680 0039d316-1c4b-4281-b951-d872f2087c98