SkImageDecoder: Adapt optimization to new function return type
SkImageDecoder: Adapt optimization to new function return type

onDecode is no longer a boolean type function, so we must return
the proper object for success instead of true.

Change-Id: I870922270742b9aba2eaa6334a580a35f6a8d3f6
Signed-off-by: Evan Anderson <e096fec2abea71f82bd1a5da001fc46bd3e4e228@aospa.co>

Hybrid-Rom/external_skia,Hybrid-Rom/external_skia,Hybrid-Rom/external_skia,Hybrid-Rom/external_skia,Hybrid-Rom/external_skia,Hybrid-Rom/external_skia,Hybrid-Rom/external_skia,Hybrid-Rom/external_skia