Auto merge of #18155 - ferjm:pwm.perf.timeline, r=jdm

Add paint metrics to Performance Timeline API

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #18111
- [X] There are tests for these changes

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components/script/dom/webidls/PerformancePaintTiming.webidl

@@ -0,0 +1,11 @@
+/* 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 file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * https://wicg.github.io/paint-timing/#sec-PerformancePaintTiming
+ */
+
+[Exposed=(Window,Worker)]
+interface PerformancePaintTiming : PerformanceEntry {
+};