[FPF-CI] Add duration and size metrics

Add two metrics: one for the duration on how long it takes to add noise
to the canvas. Another metric captures the size of the canvas, i.e., the
number of pixels. This does not add or modify any functionality.

Bug: 410223717, 377325952
Change-Id: Ice5449d72d80a3ecb5fbfc645fdb3368e7a1d327
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6449465
Reviewed-by: Antonio Sartori <antoniosartori@chromium.org>
Commit-Queue: Tom Van Goethem <tov@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1446621}