setTrebleTestingOverride

This is being added in preparation of removing TREBLE_TESTING_OVERRIDE
since some clients may use setenv/etc in a multithreaded environment
which break the use of getenv to retrieve the value of this flag.

Bug: 156668058
Test: tests using either flag still work
Change-Id: I53e3fafa373e19814d9533ade0587e32278dfec7
diff --git a/transport/include/hidl/ServiceManagement.h b/transport/include/hidl/ServiceManagement.h
index 4573a25..c8e8f6c 100644
--- a/transport/include/hidl/ServiceManagement.h
+++ b/transport/include/hidl/ServiceManagement.h
@@ -47,6 +47,10 @@
 // e.x.: android.hardware.foo@1.0::IFoo, default
 void waitForHwService(const std::string &interface, const std::string &instanceName);
 
+// Only works on userdebug/eng builds. This allows getService to bypass the
+// VINTF manifest for testing only.
+void setTrebleTestingOverride(bool testingOverride);
+
 void preloadPassthroughService(const std::string &descriptor);
 
 // Returns a service with the following constraints: