Guard against negative timestamps in trace processor (prev: screenshots track crashes when opening trace in UI)

[cphlipot1]

I'm seeing the screenshots track crash when opening a trace in the UI despite my trace having no screenshots.

I've created a simplified synthetic trace with 9 packets to reproduce this issue, which i believe should still be a valid trace despite being manually constructed: crashing_trace.pftrace.zip

How to reproduce

1. open ui.perfetto.dev
2. open crashing_trace.pftrace
3. once trace loads expand all tracks (there should be two total)
4. zoom all the way out (hold 's' key)
5. observe error

To assist with debugging please attach or link to the trace you were viewing.

Viewed on: https://ui.perfetto.dev

Error: Normalization error CacheKey<0, 28521267200, 4194304, 1700> CacheKey<-893376998, 22334424944, 7030206, 1652>
Error: Normalization error CacheKey<0, 28521267200, 4194304, 1700> CacheKey<-893376998, 22334424944, 7030206, 1652>
    at ScreenshotsTrack.maybeRequestData (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:323008:21)
    at ScreenshotsTrack.renderCanvas (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:322733:20)
    at ScreenshotsTrack.render (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:322301:15)
    at TrackPanel.renderCanvas (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:321774:25)
    at PanelContainer.redrawCanvas (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:473569:26)
    at onRedraw (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:473384:38)
    at RafScheduler.syncCanvasRedraw (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:318683:14)
    at https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:318717:60
    at measure (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:318469:7)
    at RafScheduler.onAnimationFrame (https://ui.perfetto.dev/v39.0-bb663f9c4/frontend_bundle.js:318717:48)

v39.0-bb663f9c4 bb663f9c401914d29e1207171e8a37f410cf5dd2
UA: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

[LalitMaganti]

Had a look at your trace: I think the problem is actually this trace is not well formed. Specifically we have the following situation:

1. Clock 6 and 3 are synchronized at ts = 0 <-> ts = 0
2. Clock 3 is synchronized at 26366605614 to Clock 9999 at 2875714123178517
3. The first event is emitted on clock 9999 at 2875665408788047. This is converted to clock 3 at -22347784856 and onto clock 6 also at -22347784856.

Negative timestamps are not supported in trace processor (i.e. producing them is undefined behaviour): this is why the UI is crashing. We should likely have some checks against this in trace processor.