Clean up histogram'd media enum max values.

media/ffmpeg/ffmpeg_common.cc

Index: media/ffmpeg/ffmpeg_common.cc
diff --git a/media/ffmpeg/ffmpeg_common.cc b/media/ffmpeg/ffmpeg_common.cc
index 6e7bd155cd80d9f103cfbd7670e8e5381263cd3e..05dcd17155cd5b09a6066780af3b3da6c7ddc14d 100644
--- a/media/ffmpeg/ffmpeg_common.cc
+++ b/media/ffmpeg/ffmpeg_common.cc
@@ -389,9 +389,12 @@ void AVStreamToVideoDecoderConfig(
       visible_rect.size(), aspect_ratio.num, aspect_ratio.den);
 
   if (record_stats) {
+    // Note the PRESUBMIT_IGNORE_UMA_MAX below, this silences the PRESUBMIT.py
+    // check for uma enum max usage, since we're abusing
+    // UMA_HISTOGRAM_ENUMERATION to report a discrete value.
     UMA_HISTOGRAM_ENUMERATION("Media.VideoColorRange",
                               stream->codec->color_range,
-                              AVCOL_RANGE_NB);
+                              AVCOL_RANGE_NB);  // PRESUBMIT_IGNORE_UMA_MAX
   }
 
   VideoFrame::Format format = PixelFormatToVideoFormat(stream->codec->pix_fmt);