camera2-portability: Touch-to-focus accounting for effective crop

This fixes the calculation of API 2 focus and metering rectangles to account for
the effective crop region (after the framework has performed automatic cropping
to match the requested output aspect ratio). It also guards against and prints
warnings when changing the resolution after having configured the session and
surfaces; before, this was merely a silent no-op.

Bug: 17187095
Change-Id: I3243bea24d6936d1bba5d556b3846d172ad0defe