Metrics ebuild has a missing dependency since it always fails to build the first time but is successful on a rebuild.

e.g. 
https://uberchromegw.corp.google.com/i/chromeos/builders/daisy-release/builds/1628
https://uberchromegw.corp.google.com/i/chromeos/builders/daisy-release/builds/1629
https://uberchromegw.corp.google.com/i/chromeos/builders/daisy-release/builds/1630


WARNING: The following packages failed once or more,
but succeeded upon retry. This might indicate incorrect
dependencies.
  chromeos-base/metrics-0.0.1-r2515
Merge complete