commit a02ee48ac00a247ae06f499fc7f17a6e21a6cd04
author Stephen Nusko <nuskos@google.com> Tue Jan 11 14:15:14 2022 -0500
committer Stephen Nusko <nuskos@google.com> Wed Jan 12 04:13:48 2022 +0000
tree 47c97153a0de1fa572e367a5acb5eb28e36e02b4
parent 86526cf0e512542b9609e59516ea80396e1ce3f4

Add a new "restricted" metric name to reduce noise.

Currently our breakdown metric grabs trace event names and concatenates
them to form detailed names, but often trace events aren't informative
or they are optional and will break up our aggregation into different
rows.

This new restricted_metric_name is more opiniated about which trace
events to include. It always includes the top level slice name, and if
its a PostTask where it was posted from. After that it includes only one
additional trace event using a priority list of categories from the
descendant slices.

1) mojom
2) toplevel
3) java

If there is multiple for a given category the first is used.

If there is no matching categories for the descendants (if they have
any) we will append "UnknownEvent" to ensure un classified events don't
become super common.

The test has some UnknownEvents because its missing the toplevel
category which would normally make most events not be tagged as
UnknownEvents.

Bug: 209448519
Change-Id: I23210fc53337f0bd3a5650c95e9936a1143226be