Add more image writer comments and clean up

Bug: 22858531

Change-Id: Ia3663856a7d9f67d9d9af329a54707ae2dc55a48
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index a35ba3e..cde4315 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -572,7 +572,7 @@
       SHARED_REQUIRES(Locks::mutator_lock_);
 
   void FinishInit(Thread* self)
-  SHARED_REQUIRES(Locks::mutator_lock_)
+      SHARED_REQUIRES(Locks::mutator_lock_)
       REQUIRES(!dex_lock_, !Roles::uninterruptible_);
 
   // For early bootstrapping by Init