Disallow maximize mode managed windows to be dragged

BUG=348818
TEST=unittest & visual test

Review URL: https://codereview.chromium.org/185713011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255015 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255015