Print field info on mark sweep invalid ref crash.

Bug: 20557050
Change-Id: I3abb7a44e3b7ed3256653824fd1705aac5f7d72c
diff --git a/runtime/mirror/object.h b/runtime/mirror/object.h
index f2d879f..5afe99f 100644
--- a/runtime/mirror/object.h
+++ b/runtime/mirror/object.h
@@ -439,6 +439,8 @@
   void VisitReferences(const Visitor& visitor, const JavaLangRefVisitor& ref_visitor)
       NO_THREAD_SAFETY_ANALYSIS;
 
+  ArtField* FindFieldByOffset(MemberOffset offset) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
   // Used by object_test.
   static void SetHashCodeSeed(uint32_t new_seed);
   // Generate an identity hash code. Public for object test.