googlesamples%2Fandroid-vision%2FvisionSamples%2Fmulti-tracker%2Fapp%2Fsrc%2Fmain%2Fjava%2Fcom%2Fgoogle%2Fandroid%2Fgms%2Fsamples%2Fvision%2Fface%2Fmultitracker%2Fui%2Fcamera%2FCameraSourcePreview.java