- Support loading combined trace json files from telemetry
- Add "Blink RCS" source to separate blink details
- Add prompt for naming newly loaded files
- Add Group.addsToTotal variable for easier unclassified tracking

Drive-by-fix: use let instead of var

Change-Id: I5e471d8d1462987d1da98c2229090215c1fc6179
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2273857
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68611}