Fix 2797185: Re-enable thumbnail generation in framework

This re-enables thumbnail generation code in the framework
with a few improvements.

In addition to enabling the system to capture thumbnails,
it removes padding from the borders to account for space
overlapped by system widgets (status bar, etc.). Thus,
the contents of the bitmap are only those pixels unique to
the activity.

It also maximizes resolution of the bitmap by capturing the
image in the application's current orientation. In landscape
mode, it captures a bitmap with dimensions w x h.  In portrait,
it captures a bitmap with dimensions h x w. Where w and h are
thumbnail_width and thumbnail_height as defined in dimens.xml.

Though enabled, the change is not currently used in this
branch.  The work is being checked in here to avoid
complicated downstream merges.

Change-Id: Ifc8a4e0075d7d0697d8159589be3816ace31d70c
5 files changed