Add UMA to record how long native and notification was done

For Android V, we want to understand how long we need to keep
track of the trampoline activity. So this CL records the duration
when trampoline activity received an intent, until the native is
loaded or when the notification finishes handling. This is recorded
on all versions so we can use the value to estimate the timeout
on V.

Low-Coverage-Reason: TRIVIAL_CHANGE
Bug: 365727857
Change-Id: I3dfab9d6d5ab4d87997f68546d825477fd7c88d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5949967
Commit-Queue: Min Qin <qinmin@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1373125}