Add read barriers for the class and the intern tables.

Add read barriers for the strong roots in the intern table and the
(strong) roots in the class table to make possible concurrent scanning
of them.

Bug: 12687968
Change-Id: If6edc33a37e65a8494e66dc3b144138b1530367f
diff --git a/runtime/indirect_reference_table-inl.h b/runtime/indirect_reference_table-inl.h
index 790f4d0..b787233 100644
--- a/runtime/indirect_reference_table-inl.h
+++ b/runtime/indirect_reference_table-inl.h
@@ -80,7 +80,7 @@
   mirror::Object* obj = *root;
   if (LIKELY(obj != kClearedJniWeakGlobal)) {
     // The read barrier or VerifyObject won't handle kClearedJniWeakGlobal.
-    obj = ReadBarrier::BarrierForWeakRoot<mirror::Object, kReadBarrierOption>(root);
+    obj = ReadBarrier::BarrierForRoot<mirror::Object, kReadBarrierOption>(root);
     VerifyObject(obj);
   }
   return obj;