trace_processor: properly handle and expose parent upids This change exposes the parent upid for a process if it known. It also adds some logic to handle the cases where a threaded process forks to associate the child process correctly with the upid of the parent once it becomes known. Bug: 136635390 Change-Id: Ic15c60f72f1ca23e2c2f1689323453d97094dcfc
Perfetto is an open-source project for performance instrumentation and tracing of Linux/Android/Chrome platforms and user-space apps.
See www.perfetto.dev for docs.