Fix theme differences between left/right pane problem

- Add a callback class to monitor the split behavior of the activity
  embedding and update UI if necessary.

Fixes: 279516059
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.homepage.SettingsHomepageActivity
Change-Id: I32e86265638684ddde067539a0f493be4c04afae
2 files changed