Watch out for the following case: 1. Use expects a chain output. 2. Node is expanded into multiple target ops. 3. One of the inner node produces a chain, the outer most one doesn't.
Watch out for the following case:
1. Use expects a chain output.
2. Node is expanded into multiple target ops.
3. One of the inner node produces a chain, the outer most one doesn't.


git-svn-id: a4a6f32337ebd29ad4763b423022f00f68d1c7b7@28209 91177308-0d34-0410-b5e6-96231b3b80d8

lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx,lodyagin/bare_cxx