The data collected for histogram "UMA.ProtoCompressionRatio" has not been used in the last 30 days. If this histogram is no longer needed, it should be removed.

Note from the Chrome Metrics team:
This bug was created and assigned to you because your histogram, "UMA.ProtoCompressionRatio", has not been viewed in the last 30 days. If the histogram is no longer needed, please remove it to help us and Chrome users save resources. If the histogram will be used, mark this bug as "WontFix" and we'll remind you in a few months if it's still unused. If you think there was an error, let us know at chrome-metrics-team@google.com.