Report dump counts as a stability metric.

Previously these were reported as a regular metric, against the currently running version, even though they were recorded from the previous execution, possibly from a different version.

Stability metrics are attributed to the version of the previous execution.

Also, there was an attempt to mitigate the cross-version reporting by associating each even with the version that recorded it. This is problematic for short-lived versions such as Canary.

I extracted the code, fixed the above deficiencies, wrote tests, and added functionality (also reporting the outcome of the Breakpad invocation).

BUG=460512

Committed: https://crrev.com/a11510d8e5175aa451f11b183a6668f581b4ec60
Cr-Commit-Position: refs/heads/master@{#323131}

Review URL: https://codereview.chromium.org/1038503002

Cr-Commit-Position: refs/heads/master@{#323182}
16 files changed