When an IRemoteControlDisplay registers, cause the
RemoteControlClient to send all its information to the newly
registered display.
The previous code was only sending a request for update: this
request didn't here cause the client to send the data because
a new client generation had not been synchronized among clients
and displays.
This CL uses the same code path to force an update as when audio
focus changes, or a new client registers, by calling the same
method that is called in those cases,
updateRemoteControlDisplay_syncRcs(flags).
Also in this CL: more method renames to indicate methods that
are called synchronized on mRCStack.
Change-Id: I54102f45ba1cd4812d958ecd883bec7bc45ae88f
958bba6862