SkBitmapRegionDecoderInterface provides an interface
for multiple implementations of Android's
BitmapRegionDecoder.
We already have correctness tests in DM that will enable us
to compare the quality of our various BRD implementations.
We also need these performance tests to compare the speed
of our various implementations.
BUG=skia:4357
Review URL: https://codereview.chromium.org/1344993003
