wtf/OwnPtr.h:
(WTF::OwnPtr::OwnPtr): Added constructors that take a
PassOwnPtr. Also added a copy constructor declaration that's
required when assigning a PassOwnPtr to a stack-based OwnPtr.
(WTF::operator=): Added assignment operator methods that take a
PassOwnPtr.
(WTF::swap): Reformatted.
(WTF::operator==): Whitespace changes.
(WTF::operator!=): Ditto.