[WDF] Add Windows Driver Framework files

Takern from Microsoft GitHub repo:
d9c6040fe9

Licensed under MIT

sdk/lib/drivers/wdf/shared/inc/private/common/fxautostring.hpp

@@ -0,0 +1,53 @@
+/*++
+
+Copyright (c) Microsoft Corporation
+
+Module Name:
+
+    FxAutoString.hpp
+
+Abstract:
+
+    This is the C++ header for FxAutoString which represents a UNICODE_STRING
+    and follows the RAII (resource acquisiion is initialization) pattern where
+    it frees the buffer when the struct goes out of scope.
+
+Author:
+
+
+
+Revision History:
+
+
+
+--*/
+
+#ifndef _FXAUTOSTRING_H_
+#define _FXAUTOSTRING_H_
+
+struct FxAutoString {
+    FxAutoString(
+        VOID
+        )
+    {
+        RtlZeroMemory(&m_UnicodeString, sizeof(m_UnicodeString));
+    }
+
+    ~FxAutoString(
+        VOID
+        )
+    {
+        if (m_UnicodeString.Buffer != NULL) {
+#if _WDFLDR_
+            ExFreePool(m_UnicodeString.Buffer);
+#else
+            FxPoolFree(m_UnicodeString.Buffer);
+#endif
+            RtlZeroMemory(&m_UnicodeString, sizeof(m_UnicodeString));
+        }
+    }
+
+    UNICODE_STRING m_UnicodeString;
+};
+
+#endif // _FXAUTOSTRING_H_