[perf_skottiewasm_lottieweb] Enable GPU tracing

Not consumed by any scripts ATM, but useful for manual trace inspection.

Change-Id: I2b2e2ad227278f6527454628475143294c655835
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/226976
Commit-Queue: Florin Malita <fmalita@chromium.org>
Commit-Queue: Ravi Mistry <rmistry@google.com>
Auto-Submit: Florin Malita <fmalita@chromium.org>
Reviewed-by: Ravi Mistry <rmistry@google.com>
2 files changed