Update immersive confirmation.

1. Disable panic mechanism for expanded desktop.
2. Separate confirmation for each expanded desktop style.
3. Add new layout for the case when navigation
   bar is hidden but statusbar is visible.

Change-Id: I5914d655bd5f9315ac4cc6fc7d70cc4ee45bb7b2

Conflicts:

	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java