[WDF] Add Windows Driver Framework files

Takern from Microsoft GitHub repo:
d9c6040fe9

Licensed under MIT

sdk/lib/drivers/wdf/shared/primitives/um/mxfileobjectum.cpp

@@ -0,0 +1,41 @@
+/*++
+
+Copyright (c) Microsoft Corporation
+
+ModuleName:
+
+    MxFileObjectUm.cpp
+
+Abstract:
+
+    Implementation of MxFileObjectUm functions.
+
+Author:
+
+Revision History:
+
+
+
+--*/
+
+#include "Mx.h"
+
+#include <strsafe.h>
+
+#include "fxmin.hpp"
+
+PUNICODE_STRING
+MxFileObject::GetFileName(
+    _Inout_opt_ PUNICODE_STRING Filename
+   )
+{
+    LPCWSTR name;
+
+    ASSERTMSG("Filename parameter cannot be NULL\n", Filename != NULL);
+
+    name = m_FileObject->GetName();
+    RtlInitUnicodeString(Filename, name);
+
+    return Filename;
+}
+