Merge "Allow multiple close transactions for task view" into udc-qpr-dev

        if (taskView == null) return null;

        // Opening types should all be initiated by shell

        if (!TransitionUtil.isClosingType(request.getType())) return null;

        PendingTransition pending = findPendingCloseTransition(taskView);

        if (pending == null) {

            pending = new PendingTransition(request.getType(), null, taskView, null /* cookie */);

        }

        if (pending.mClaimed != null) {

            throw new IllegalStateException("Task is closing in 2 collecting transitions?"

                    + " This state doesn't make sense");

        }

        PendingTransition pending = new PendingTransition(request.getType(), null,

                taskView, null /* cookie */);

        pending.mClaimed = transition;

        mPending.add(pending);

        return new WindowContainerTransaction();

    }