Fix PagedTileLayout reveal animation crash.

- Use ViewPager's fake dragging API instead of manually changing scroll
positions to ensure proper touch handling during the drag animation.
- Fixed bug where reveal did not work in RTL languages.
- Ensure endFakeDrag is called for all code paths that call
startFakeDrag (this was the cause of the original revert)

Change-Id: I7f62c60829719dffc7327908ec8c5afd7dcace8f
Fixes: 111845732
Test: manual