Add test for multithreaded ActiveVerifier behavior.

base/win/scoped_handle.h

Index: base/win/scoped_handle.h
diff --git a/base/win/scoped_handle.h b/base/win/scoped_handle.h
index ac01485ab53c2ca453bff6cef0e4b88a8b70d0da..6603e681109d6b0d1c342f7e42898d04a4a712fd 100644
--- a/base/win/scoped_handle.h
+++ b/base/win/scoped_handle.h
@@ -171,13 +171,17 @@ typedef GenericScopedHandle<HandleTraits, VerifierTraits> ScopedHandle;
 // This function may be called by the embedder to disable the use of
 // VerifierTraits at runtime. It has no effect if DummyVerifierTraits is used
 // for ScopedHandle.
-void BASE_EXPORT DisableHandleVerifier();
+BASE_EXPORT void DisableHandleVerifier();
 
 // This should be called whenever the OS is closing a handle, if extended
 // verification of improper handle closing is desired. If |handle| is being
 // tracked by the handle verifier and ScopedHandle is not the one closing it,
 // a CHECK is generated.
-void BASE_EXPORT OnHandleBeingClosed(HANDLE handle);
+BASE_EXPORT void OnHandleBeingClosed(HANDLE handle);
+
+// This testing function returns the module that the ActiveVerifier concrete
+// implementation was instantiated in.
+BASE_EXPORT HMODULE GetHandleVerifierModuleForTesting();
 
 }  // namespace win
 }  // namespace base