Merge "Ensure there's a valid handler when registering a sessions listener" into lmp-dev

    void startListeningToSessions() {

        final ComponentName listenerComponent = new ComponentName(mContext,

                mOnClientUpdateListener.getClass());

        Handler handler = null;

        if (Looper.myLooper() == null) {

            handler = new Handler(Looper.getMainLooper());

        }

        mSessionManager.addOnActiveSessionsChangedListener(mSessionListener, listenerComponent,

                UserHandle.myUserId(), null);

                UserHandle.myUserId(), handler);

        mSessionListener.onActiveSessionsChanged(mSessionManager

                .getActiveSessions(listenerComponent));

        if (DEBUG) {