Incorrect rendering with long traces (thousands of seconds)

[ilyapopov]

I am using SpeedScope to view Chrome Trace Events tracing file, and for long traces rendering seems incorrect. It looks like the problem occurs when the timestamp becomes larger then 31 or 32 bit (total trace duration is about 6 billion microseconds = 6000 seconds in my case). (Perfetto shows this trace well enough).

I will try to produce a shareable reproducer later.