Add lock owner information for class Monitor and add assertions for wait/notify/notifyall.

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 95 matching lines @@
   void Exit();
 
   // Wait for notification or timeout.
   WaitResult Wait(int64_t millis);
   WaitResult WaitMicros(int64_t micros);
 
   // Notify waiting threads.
   void Notify();
   void NotifyAll();
 
+#if defined(DEBUG)
+  bool IsOwnedByCurrentThread() const {
+    return owner_ == OSThread::GetCurrentThreadId();
+  }
+#else
+  bool IsOwnedByCurrentThread() const {
+    UNREACHABLE();
+    return false;
+  }
+#endif
+
  private:
   MonitorData data_;  // OS-specific data.
+#if defined(DEBUG)
+  ThreadId owner_;
+#endif  // defined(DEBUG)
 
   DISALLOW_COPY_AND_ASSIGN(Monitor);
 };
 
 
 }  // namespace dart
 
 
 #endif  // VM_OS_THREAD_H_