Use self:: instead of MassMessage::

Change-Id: I3b58b3f6aeb1c09f39cf123a1d24244f361630a7
The checkbox for sending a global message was removed in 8b5027342.

Change-Id: Icfa0de8530259d92f27880778bca893a0a55d4be
Merge "The checkbox for sending a global message was removed in 8b5027342."
Merge "Use self:: instead of MassMessage::"