Generalize the condition to take task snapshot when entering AOD

There is no guarantee that AOD or keyguard will show together
or individually (depends on SystemUI). So this change allows to
take snapshot for both cases.

Bug: 182571838
Test: 1. Enable "Always show time and info".
      2. Open any app and go to home.
      3. Launch the app again and make some changes to its content.
      4. Press power key to enter dozing.
      5. Unlock and check if the animation has the latest content.

Change-Id: Ib60b00e96632d38fac308b8851cd59b71142f321