libbinder: Session ID implemented directly.

In preparation for removing RpcAddress.

Bug: 182940634
Test: binderRpcTest (w & w/o LOG_RPC_DETAIL)
Change-Id: I945e650bbab9f8df4f785b689983b62c59bb8674
diff --git a/libs/binder/RpcState.h b/libs/binder/RpcState.h
index 1446eec..b8cf2db 100644
--- a/libs/binder/RpcState.h
+++ b/libs/binder/RpcState.h
@@ -73,7 +73,7 @@
     status_t getMaxThreads(const sp<RpcSession::RpcConnection>& connection,
                            const sp<RpcSession>& session, size_t* maxThreadsOut);
     status_t getSessionId(const sp<RpcSession::RpcConnection>& connection,
-                          const sp<RpcSession>& session, RpcAddress* sessionIdOut);
+                          const sp<RpcSession>& session, std::vector<uint8_t>* sessionIdOut);
 
     [[nodiscard]] status_t transact(const sp<RpcSession::RpcConnection>& connection,
                                     const sp<IBinder>& address, uint32_t code, const Parcel& data,