Updated printing in Gallery due to API changes.

1. Now there is two fitting modes: scale to fill and scale to fit.
   Updated the Gallery print code to support them both.

2. Now we have APIs for specifying which constraints in the print
   attributes have been satisfied by the app so the pritner does
   not satisfy them again, e.g. if the app rotated the content then
   the printer should not do it.

Change-Id: I78b2925965068bd528fe6ec739bfd1e93084dd24