A new protobuf message named Upload is defined to send build metrics
to the Android Build Server API after a build is completed. These
metrics are collected from googlers only, as described in
go/local-developers-metrics-wfh.
Bug: b/140638454
Test: m nothing
Change-Id: I5e49b5ace053913be2b75673cb1375f4cef37825
Test: Dumped the text formated based metrics file to out dir,
and checked the file.
Bug: b/63815990
Change-Id: Iff476f72a0be74eb53b6b26ef468d11c0f24a404