Add adapt_scan experimental flag
Add adapt_scan experimental flag

Change-Id: Id2fd7fcb2240fbcf9384b3c9b2be5fe15fd1945f

smarter/aom,mbebenita/aom,smarter/aom,luctrudeau/aom,GrokImageCompression/aom,mbebenita/aom,smarter/aom,GrokImageCompression/aom,smarter/aom,mbebenita/aom,mbebenita/aom,smarter/aom,luctrudeau/aom,mbebenita/aom,luctrudeau/aom,mbebenita/aom,mbebenita/aom,mbebenita/aom,GrokImageCompression/aom,mbebenita/aom,luctrudeau/aom,GrokImageCompression/aom,GrokImageCompression/aom,luctrudeau/aom,luctrudeau/aom,GrokImageCompression/aom,smarter/aom