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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
"use strict";
const {
TYPES: { REFLOW },
const {
getLayoutChangesObserver,
releaseLayoutChangesObserver,
class ReflowWatcher {
/**
* Start watching for reflows related to a given Target Actor.
*
* @param TargetActor targetActor
* The target actor from which we should observe reflows
* @param Object options
* Dictionary object with following attributes:
* - onAvailable: mandatory function
* This will be called for each resource.
*/
async watch(targetActor, { onAvailable }) {
// Only track reflow for non-ParentProcess FRAME targets
if (
targetActor.targetType !== Targets.TYPES.FRAME ||
targetActor.typeName === "parentProcessTarget"
) {
return;
}
this._targetActor = targetActor;
const onReflows = reflows => {
onAvailable([
{
resourceType: REFLOW,
reflows,
},
]);
};
this._observer = getLayoutChangesObserver(targetActor);
this._offReflows = this._observer.on("reflows", onReflows);
this._observer.start();
}
destroy() {
releaseLayoutChangesObserver(this._targetActor);
if (this._offReflows) {
this._offReflows();
this._offReflows = null;
}
}
}
module.exports = ReflowWatcher;