We should be consistent about what we suggestion.  See this message below:

>>>
git cl upload
Running presubmit upload checks ...
Done processing D:\src\chrome2\src\chrome\browser\metrics\process_memory_metrics_emitter.cc
ERROR:root:histograms.xml is not formatted correctly; run pretty_print.py to fix.

** Presubmit Messages **
Missing OWNER reviewers for these files:
    tools\metrics\histograms\histograms.xml

Suggested OWNERS: (Use "git-cl owners" to interactively select owners.)
    isherman@chromium.org

** Presubmit ERRORS **
histograms.xml is not formatted correctly; please run git cl format D:\src\chrome2\src\tools\metrics\histograms to fix.

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First confusing thing above is that it says to both use pretty_print and git cl format. Shouldn't it be just one tool?
>>>