Move the JPEGData used to build histograms to local scope.
Move the JPEGData used to build histograms to local scope.

guanzidashu/guetzli_ios_metal,google/guetzli,ianhuang-777/guetzli,szabadka/guetzli,dloeng/guetzli,guanzidashu/guetzli_ios_metal,ianhuang-777/guetzli,google/guetzli,szabadka/guetzli,dloeng/guetzli,guanzidashu/guetzli_ios_metal,ianhuang-777/guetzli,google/guetzli,guanzidashu/guetzli_ios_metal,szabadka/guetzli,dloeng/guetzli,ianhuang-777/guetzli,google/guetzli