Always define IsOwnedByCurrentThread

runtime/vm/os_thread.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OS_THREAD_H_
 #define VM_OS_THREAD_H_
 
 #include "platform/globals.h"
 #include "vm/globals.h"
 
@@ skipping 56 matching lines @@
   ~Mutex();
 
   void Lock();
   bool TryLock();
   void Unlock();
 
 #if defined(DEBUG)
   bool IsOwnedByCurrentThread() const {
     return owner_ == OSThread::GetCurrentThreadId();
   }
-#endif  // defined(DEBUG)
+#else
+  bool IsOwnedByCurrentThread() const {
+    UNREACHABLE();
+    return false;
+  }
+#endif
 
  private:
   MutexData data_;
 #if defined(DEBUG)
   ThreadId owner_;
 #endif  // defined(DEBUG)
 
   DISALLOW_COPY_AND_ASSIGN(Mutex);
 };
 
@@ skipping 25 matching lines @@
   MonitorData data_;  // OS-specific data.
 
   DISALLOW_COPY_AND_ASSIGN(Monitor);
 };
 
 
 }  // namespace dart
 
 
 #endif  // VM_OS_THREAD_H_