Add missing include
Add missing include

okuta/chainer,chainer/chainer,jnishi/chainer,jnishi/chainer,jnishi/chainer,chainer/chainer,jnishi/chainer,chainer/chainer,niboshi/chainer,keisuke-umezawa/chainer,niboshi/chainer,keisuke-umezawa/chainer,hvy/chainer,hvy/chainer,wkentaro/chainer,hvy/chainer,ktnyt/chainer,wkentaro/chainer,hvy/chainer,wkentaro/chainer,okuta/chainer,ktnyt/chainer,keisuke-umezawa/chainer,ktnyt/chainer,okuta/chainer,niboshi/chainer,ktnyt/chainer,wkentaro/chainer,okuta/chainer,tkerola/chainer,niboshi/chainer,pfnet/chainer,keisuke-umezawa/chainer,chainer/chainer