Fixes the build break from 4192.

Patch by: amitmanjhi
Review by: spoon



git-svn-id: https://google-web-toolkit.googlecode.com/svn/releases/1.6@4198 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java b/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java
index b7c87d2..bf21c88 100644
--- a/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java
+++ b/tools/api-checker/test/com/google/gwt/tools/apichecker/ApiContainerTest.java
@@ -68,6 +68,11 @@
     public boolean isGenerated() {
       return false;
     }
+
+    @Override
+    public boolean isSuperSource() {
+      return false;
+    }
   }
 
   @SuppressWarnings("unused")