feat: js runtime switching C API for Swift

[okwasniewski]

Summary:

Note

This PR is part of JavaScriptCore Extraction to this repository: https://github.com/react-native-community/javascriptcore

This PR implements a C API to switch JS Engines that can be used from Swift.

Here is an example:

import React
import React_RCTAppDelegate
import ReactAppDependencyProvider
import UIKit
import RCTRuntime

class ReactNativeDelegate: RCTDefaultReactNativeFactoryDelegate {
  override func sourceURL(for bridge: RCTBridge) -> URL? {
    self.bundleURL()
  }

  override func bundleURL() -> URL? {
    #if DEBUG
    RCTBundleURLProvider.sharedSettings().jsBundleURL(forBundleRoot: "index")
    #else
    Bundle.main.url(forResource: "main", withExtension: "jsbundle")
    #endif
  }

  override func createJSRuntimeFactory() -> JSRuntimeFactory {
    jsrt_create_jsc_factory() // Easily switch engines here
  }
}

Changelog:

[IOS] [ADDED] - js runtime C API for Swift

Test Plan:

CI Green

[cipolleschi]

Looks good to me, I just left a question

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@cipolleschi has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[Kudo]

also looks good to me. thanks for following up my questions

[facebook-github-bot]

@cipolleschi merged this pull request in a6607c0.