Merge changes Iafce68b6,I3b96a351,Ic2476c3d,I0cc2588c,I83f4795e, ...

* changes:
  Remove redundant prefix from UnbindReason
  Extract UnbindReason from InputMethodClient
  Remove redundant prefix from StartInputReason
  Extract StartInputReason from InputMethodClient
  Move some methods from InputMethodClient to InputMethodDebug
  Enable @UnbindReason annotation in IMMS
  Enable @StartInputReason annotation in IMMS
  Enable @SoftInputModeFlags annotation in IMMS
  Enable @MissingMethodFlags annotation in IMMS