Refactor the lockscreen camera widget, removing the bitmap.

The new approach is to create two views:
 - Widget preview, drawn at full-size, then scaled to fit frame.
 - Fullscreen preview, drawn at full-size, used during animation.

Two views are necessary to both ensure the widget scrolls properly
with the widget page yet still appears to scale up and match
the camera app pixel for pixel.

The offscreen bitmap and associated background rendering is no
longer necessary.  This avoids the large allocation and associated
rendering time after turning screen on.

Also fixes 1px horizontal discrepancy during old scale-up anim.

Also suppresses long-click behavior on the camera widget.

Bug:7471107
Bug:7559755
Change-Id: I1d834aa743bc05d6a7e2ce3eadfee8d5ff40da37