Don't use PassRefPtr arguments for Range constructors/factories.

This usage of PassRefPtr was wrong because it didn't move ownership of
objects. We should use raw pointers and increase reference counters when it is
necessary.

BUG=none
TEST=none; no behavior changes.

Review URL: https://chromiumcodereview.appspot.com/23506015

git-svn-id: svn://svn.chromium.org/blink/trunk@157067 bbb929c8-8fbe-4397-9dbb-9b2b20218538