Avoid copying and strlen(3) in the FindClass path.

Change-Id: I789f3c883596d1852a2c1954ce7a207e6f937117
diff --git a/src/image_writer.h b/src/image_writer.h
index b6b02f4..d27333a 100644
--- a/src/image_writer.h
+++ b/src/image_writer.h
@@ -98,6 +98,7 @@
   }
 
   bool IsImageClass(const Class* klass);
+  void DumpImageClasses();
 
   void PruneNonImageClasses();
   static bool NonImageClassesVisitor(Class* c, void* arg);