The following is the validation messages from webidl2.js, which may help understanding this PR:
Validation error at line 1 in performance-timeline-2,2:
callback PerformanceObserverCallback = void (PerformanceObserverEntryList entries,
^ `void` is now replaced by `undefined`. Refer to the [relevant GitHub issue](https://github.com/heycam/webidl/issues/60) for more information.
Validation error at line 7 in performance-timeline-2,2:
void observe (optional PerformanceObserverInit
^ `void` is now replaced by `undefined`. Refer to the [relevant GitHub issue](https://github.com/heycam/webidl/issues/60) for more information.
Validation error at line 8 in performance-timeline-2,2:
void disconnect ();
^ `void` is now replaced by `undefined`. Refer to the [relevant GitHub issue](https://github.com/heycam/webidl/issues/60) for more information.
:boom: Error: 500 Internal Server Error :boom:
PR Preview failed to build. (Last tried on Aug 18, 2020, 4:34 PM UTC).
More
PR Preview relies on a number of web services to run. There seems to be an issue with the following one:
:rotating_light: [Spec Generator](https://www.w3.org/2015/labs/) - Spec Generator is the web service used to build specs that rely on ReSpec.
:link: [Related URL](https://labs.w3.org/spec-generator/?type=respec&url=https%3A%2F%2Frawcdn.githack.com%2Fautokagami%2Fperformance-timeline%2F896ef7decbd46bb281d5103af46f34c3336a4ea5%2Findex.html%3FisPreview%3Dtrue)
```
😭 Sorry, there was an error generating the HTML. Please report this issue!
[36mSpecification: https://rawcdn.githack.com/autokagami/performance-timeline/896ef7decbd46bb281d5103af46f34c3336a4ea5/index.html?isPreview=true&publishDate=2020-08-18[39m
[36mReSpec version: 25.13.0[39m
[36mFile a bug: https://github.com/w3c/respec/[39m
[36mError: Error: Evaluation failed: Timeout: document.respecIsReady didn't resolve in 10208ms.[39m
[36m at ExecutionContext._evaluateInternal (/u/spec-generator/node_modules/puppeteer/lib/cjs/puppeteer/common/ExecutionContext.js:217:19)[39m
[36m at runMicrotasks ()[39m
[36m at processTicksAndRejections (internal/process/task_queues.js:97:5)[39m
[36m at async ExecutionContext.evaluate (/u/spec-generator/node_modules/puppeteer/lib/cjs/puppeteer/common/ExecutionContext.js:106:16)[39m
[36m at async generateHTML (/u/spec-generator/node_modules/respec/tools/respecDocWriter.js:128:12)[39m
[36m at async fetchAndWrite (/u/spec-generator/node_modules/respec/tools/respecDocWriter.js:95:18)[39m
[36m at async Object.generate [as respec] (/u/spec-generator/generators/respec.js:14:20)[39m
[36m at async generate (/u/spec-generator/server.js:90:29)[39m
[36m[39m
```
_If you don't have enough information above to solve the error by yourself (or to understand to which web service the error is related to, if any), please [file an issue](https://github.com/tobie/pr-preview/issues/new?title=Error%20not%20surfaced%20properly&body=See%20w3c/performance-timeline%23174.)._
This is an automated pull request to align the spec with the latest Web IDL specification.
Currently the autofix might introduce some awkward code formatting, so please feel free to modify the formatting.
Please file an issue on https://github.com/saschanaz/webidl-updater/issues/new if you think this PR is invalid or should be enhanced.
The following is the validation messages from webidl2.js, which may help understanding this PR:
:boom: Error: 500 Internal Server Error :boom:
PR Preview failed to build. (Last tried on Aug 18, 2020, 4:34 PM UTC).
More
PR Preview relies on a number of web services to run. There seems to be an issue with the following one: :rotating_light: [Spec Generator](https://www.w3.org/2015/labs/) - Spec Generator is the web service used to build specs that rely on ReSpec. :link: [Related URL](https://labs.w3.org/spec-generator/?type=respec&url=https%3A%2F%2Frawcdn.githack.com%2Fautokagami%2Fperformance-timeline%2F896ef7decbd46bb281d5103af46f34c3336a4ea5%2Findex.html%3FisPreview%3Dtrue) ``` 😭 Sorry, there was an error generating the HTML. Please report this issue! [36mSpecification: https://rawcdn.githack.com/autokagami/performance-timeline/896ef7decbd46bb281d5103af46f34c3336a4ea5/index.html?isPreview=true&publishDate=2020-08-18[39m [36mReSpec version: 25.13.0[39m [36mFile a bug: https://github.com/w3c/respec/[39m [36mError: Error: Evaluation failed: Timeout: document.respecIsReady didn't resolve in 10208ms.[39m [36m at ExecutionContext._evaluateInternal (/u/spec-generator/node_modules/puppeteer/lib/cjs/puppeteer/common/ExecutionContext.js:217:19)[39m [36m at runMicrotasks (