glretrace: Show current frame number in window title

I find this can be useful to roughly identify which frames I want to be
looking at for a specific issue in a large trace, by replaying the trace
and looking at the current frame number when the issue occurs.

Change-Id: I53cdab0c3cffdd6944fc0bd6206de4b99990913b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/apitrace/+/2224541
Reviewed-by: Po-Hsien Wang <pwang@chromium.org>
Commit-Queue: Robert Tarasov <tutankhamen@chromium.org>
Tested-by: Robert Tarasov <tutankhamen@chromium.org>
5 files changed