Follow-up to #77652: each runFlush registered a fresh requestAnimationFrame and never cancelled it. Chromium parks rAF callbacks for hidden renderers, so a long hidden stream at the 33ms floor accumulates thousands of parked closures that all fire in the first frame on refocus (all but one no-oping through the stale-frame guard). Track the pending handle, cancel it before requesting a new one (only the newest flush's measurement matters), and cancel on unmount.
kshitij
c4ac62a7ee