Fix regression; once again we can apply Gallery photo to contact.

The changes to support hi-res photos in Ic0cabaa5 were not applied to
AttachPhotoActivity.  This CL makes the analogous changes, and many other
cleanups besides.

In addition, applying the Gallery photo works even if the AttachPhotoActivity
is killed (eg: when selecting a contact, or when cropping the photo); this
didn't work even before the regression.

The save-contact Intent which invokes the ContactSaveService no longer
needs to specify a callback Activity (it is OK to pass null if you don't
care about getting a callback).

The subclasses of PhotoSelectionHandler have been significantly simplified,
partly by pushing common behavior to the superclass, and also by directly
accessing state in their outer class instead making their own copies.

ContactLoader.Result.getEntityDeltaList() is a new instance method that
replaces more verbose incantations.

New utility class, ContactPhotoUtils.  Helps with compressing Bitmaps, and
generating temp-file names used when saving hi-res photos to a contact.

Bug: 6298601
Change-Id: I2fe90c33c9fa81716f263d82ed80c0d6f63c6a7e