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// Given a resource name, returns a promise that will resolve to the
// corresponding PerformanceResourceTiming entry. The promise will reject,
// however, if the PerformanceResourceTiming entry isn't observed within ~2
// seconds (scaled according to WPT timeout scaling).
const observe_entry = entry_name => {
const entry = new Promise(resolve => {
new PerformanceObserver((entry_list, observer) => {
for (const entry of entry_list.getEntries()) {
if (entry.name.endsWith(entry_name)) {
resolve(entry);
observer.disconnect();
return;
}
}
}).observe({"type": "resource", "buffered": true});
});
const timeout = new Promise((resolve, reject) => {
step_timeout(() => {
reject(new Error("observe_entry: timeout"));
}, 2000);
});
// If the entry isn't observed within 2 seconds, assume it will never show
// up.
return Promise.race([entry, timeout]);
};