Implement the legacy splash screen behavior

For apps opted out of the new splash screen, we show the full background
drawable.
Ensure there has send the splash screen background color to
StartingWindowListener.

Bug: 182880656
Test: manual set useLegacy to true then verify legacy splash screen.
Test: atest WmTests:ActivityRecordTests
Test: atest StartingSurfaceDrawerTests

Change-Id: Icf662f3c5f368f447e718f82f78dc25b909ca9be
10 files changed