08c703a7b8
[ Merge of http://go/wvgerrit/137951 ] ValueMetric was not checking whether certain unsigned types will overflow when casted to protobuf's signed int64 type. This CL adds a max value to prevent potential overflows. The value metric has also been updated to an emum to represent its possible three state, as opposed to using two boolean flags. For basic value metrics, this saves about 4 bytes of space. This works out to being ~100 bytes per crypto session, ~20 bytes per CDM session and ~20 bytes per engine metrics. Bug: 204946540 Test: Metric unit tests Change-Id: I688bece8f31cccaf2a25bd8f99d9b080b0efd0de