Use current display surface size for custom rotation animation

The animation starts after the display has been rotated, so the current
size is available to use as how the normal rotation is configured.

Fixes: 151135285
Test: Rotate an activity with ROTATION_ANIMATION_CROSSFADE and
      check there is no split effect in the center of screen.
Change-Id: I68cc4c83983210e87c44014817ff4b84305ba32d