Add missing @Override to DroidDoc and ApiCheck

Change-Id: Ic7829a4ea62a614ef8b525bd84f8fbaaa4674d06
diff --git a/tools/droiddoc/src/PackageInfo.java b/tools/droiddoc/src/PackageInfo.java
index 18c636e..17ad1b7 100644
--- a/tools/droiddoc/src/PackageInfo.java
+++ b/tools/droiddoc/src/PackageInfo.java
@@ -57,11 +57,13 @@
         return s;
     }
 
+    @Override
     public ContainerInfo parent()
     {
         return null;
     }
 
+    @Override
     public boolean isHidden()
     {
         return comment().isHidden();