Scaffolding for the PerformanceObserver TurboModule (C++ side) (#35226)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/35226

Changelog: [Internal]

This adds scaffolding for the C++ side of NativePerformanceObserver module.

Thanks to christophpurrer for helping set this up, as this is the first one of this kind inside core/OSS.

Reviewed By: rubennorte

Differential Revision: D41028555

fbshipit-source-id: 4acf0e71a254a42044cbbe5f94f40938342c6aa2

Libraries/WebPerformance/NativePerformanceObserver.js

@@ -0,0 +1,41 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict
+ * @format
+ */
+
+import type {TurboModule} from '../TurboModule/RCTExport';
+
+import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';
+
+export const RawPerformanceEntryTypeValues = {
+  UNDEFINED: 0,
+};
+
+export type RawPerformanceEntryType = number;
+
+export type RawPerformanceEntry = $ReadOnly<{
+  name: string,
+  entryType: RawPerformanceEntryType,
+  startTime: number,
+  duration: number,
+  // For "event" entries only:
+  processingStart?: number,
+  processingEnd?: number,
+  interactionId?: number,
+}>;
+
+export interface Spec extends TurboModule {
+  +startReporting: (entryType: string) => void;
+  +stopReporting: (entryType: string) => void;
+  +getPendingEntries: () => $ReadOnlyArray<RawPerformanceEntry>;
+  +setOnPerformanceEntryCallback: (callback?: () => void) => void;
+}
+
+export default (TurboModuleRegistry.get<Spec>(
+  'NativePerformanceObserverCxx',
+): ?Spec);