Enable chroma-sub8x8 by default
Enable chroma-sub8x8 by default

Change-Id: I3f73ccdb82261d13580697c162b7f5c877616f32

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom