Fix a bootloop problem when /data/system/usagestats/usage-history.xml is empty.
This often occurs after an incomplete reboot/shutdown or battery pull.

Change-Id: I4f01151f4051df4ae1b85fa460ec7a9e70122878
Make ImageView drawable update more efficient in some cases.

When updating the view's drawable via setImageResource or setImageURI,
make sure to skip the layout pass if the old and new drawable have equal
sizes. This follows what is already done for setDrawable().

Change-Id: If73d225e38d0a2f7c616c4aeb33f67bdaed390f1