Implement simple class merger.

BUG=

Change-Id: Ib22cf7a7d10797b0ba7ed6ef8fb5aa5fda9aaa60

diff --git a/src/test/examples/classmerging/ConflictingInterface.java b/src/test/examples/classmerging/ConflictingInterface.java
new file mode 100644
index 0000000..6202e3c
--- /dev/null
+++ b/src/test/examples/classmerging/ConflictingInterface.java
@@ -0,0 +1,9 @@
+// Copyright (c) 2017, 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 classmerging;
+
+public interface ConflictingInterface {
+
+  public String method();
+}