Revert "Add support for closing Android Shell instances from Java."

This causes some layout tests on Android to crash with a NPE.

TBR=tedchoc@chromium.org,avi@chromium.org

Review URL: https://codereview.chromium.org/130503003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244118 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244118