Add functions to query #threads and looper state.

Can't submit until we can make ABI changes to libhwbinder.

Bug: 35117173
Test: boots
Change-Id: I10eeb128998e94b583be50c9968603ab656f0f28
diff --git a/include/hwbinder/ProcessState.h b/include/hwbinder/ProcessState.h
index 5441b75..305ee11 100644
--- a/include/hwbinder/ProcessState.h
+++ b/include/hwbinder/ProcessState.h
@@ -64,6 +64,7 @@
             void                spawnPooledThread(bool isMain);
 
             status_t            setThreadPoolConfiguration(size_t maxThreads, bool callerJoinsPool);
+            size_t              getMaxThreads();
             void                giveThreadPoolName();
 
             ssize_t             getKernelReferences(size_t count, uintptr_t* buf);