Fix object verification.

Refactor VERIFY_OBJECT_ENABLED to become less brittle to change enum and global
constant.

Change-Id: Ie405106be81dce9a913730c7f46a5659582fa18b
diff --git a/src/thread.h b/src/thread.h
index 1992dc9..dd67a21 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -401,11 +401,7 @@
   void VerifyRoots(VerifyRootVisitor* visitor, void* arg)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
-#if VERIFY_OBJECT_ENABLED
   void VerifyStack() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-#else
-  void VerifyStack() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_){}
-#endif
 
   //
   // Offsets of various members of native Thread class, used by compiled code.
@@ -610,6 +606,8 @@
   }
   friend class SignalCatcher;  // For SetStateUnsafe.
 
+  void VerifyStackImpl() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
   void DumpState(std::ostream& os) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   void DumpStack(std::ostream& os) const
       LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_)