asyncio: Add __weakref__ slots to Handle and CoroWrapper. Upstream issue #166.
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index e8ee947..45a6342 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -36,7 +36,7 @@
 class CoroWrapper:
     # Wrapper for coroutine in _DEBUG mode.
 
-    __slots__ = ['gen', 'func', '__name__', '__doc__']
+    __slots__ = ['gen', 'func', '__name__', '__doc__', '__weakref__']
 
     def __init__(self, gen, func):
         assert inspect.isgenerator(gen), gen