Convert to use int64_t to aovid int oout-of-range
Convert to use int64_t to aovid int oout-of-range

BUG=aomedia:518

Change-Id: Ia88b50b084c6370073ac4916e00a019963cf0254

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