Merge "doc getCallingPid zero return" into main

     * If the current thread is not currently executing an incoming transaction,

     * then its own PID is returned.

     *

     * Warning: oneway transactions do not receive PID.

     * Warning: oneway transactions do not receive PID. Even if you expect

     * a transaction to be synchronous, a misbehaving client could send it

     * as a asynchronous call and result in a 0 PID here. Additionally, if

     * there is a race and the calling process dies, the PID may still be

     * 0 for a synchronous call.

     */

    @CriticalNative

    public static final native int getCallingPid();