Clean up unnecessary interfaces of WindowManagerPolicy

Since the major layout policy has been moved from PhoneWindowManager
to DisplayPolicy. The interfaces are no longer needed for cross
package access.

Only rename/remove unused methods and interfaces. No logic change.

Bug: 159104050
Test: atest WmTests
Change-Id: Ie04fe81e4fbac8df1fbbd28fcf08e4916d382a72
25 files changed