Reproduce Mockito's mock of empty interface after devirtualization.

Bug: 120675359
Change-Id: I77fe93d4af84dbe97870278cf62cbd030d680b7a
diff --git a/src/test/examples/mockito_interface/InterfaceUser.java b/src/test/examples/mockito_interface/InterfaceUser.java
new file mode 100644
index 0000000..67729d6
--- /dev/null
+++ b/src/test/examples/mockito_interface/InterfaceUser.java
@@ -0,0 +1,24 @@
+// Copyright (c) 2018, the R8 project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+package mockito_interface;
+
+public class InterfaceUser {
+
+  private Interface itf;
+
+  public InterfaceUser(Interface itf) {
+    this.itf = itf;
+  }
+
+  void consume() {
+    itf.onEnterForeground();
+  }
+
+  public static void main() {
+    Implementer impl = new Implementer();
+    InterfaceUser user = new InterfaceUser(impl);
+    user.consume();
+  }
+
+}