Merge "Fix NPE when quick switch on shell transition" into tm-dev

        // Once the pending enter transition got merged, make sure to bring divider bar visible and

        // clear the pending transition from cache to prevent mess-up the following state.

        if (transition == mSplitTransitions.mPendingEnter) {

            finishEnterSplitScreen(null);

            final SurfaceControl.Transaction t = mTransactionPool.acquire();

            finishEnterSplitScreen(t);

            mSplitTransitions.mPendingEnter = null;

            t.apply();

            mTransactionPool.release(t);

        }

    }