Provide option to not blindly foreground app's lastWindow from deepLinks

[christophpurrer]

Please select one of the following

• I am removing an existing difference between facebook/react-native and microsoft/react-native-macos 👍
• I am cherry-picking a change from Facebook's react-native into microsoft/react-native-macos 👍
• I am making a fix / change for the macOS implementation of react-native
• I am making a change required for Microsoft usage of react-native

Summary

Messenger Desktop is a multi-window application (chat, calling, settings, …) and we maintain the various windows with a windowNativeModule which allows JS interaction.

When receiving deep-links from other apps we don’t want to necessary re-open the lastWindow open as the deep-link might contain information about a particular scenario (open login page, start a call). Hence, we need to disable this behavior app wide and use our windowNativeModule to foreground the specific window related to the deep link.

• This change has 0 effect on other apps
• We could make this property an ivar, but then we need to manually register RCTLinkingManager.mm in ReactBridgeFactory-macOS.mm ….
• We could append a special url property to deep-links, but I think that would make the ‘API’ harder to use`

To use this 'feature' you would add this line in AppDelegate

  [RCTLinkingManager setAlwaysForegroundLastWindow:NO]; // <- Add this
  [[NSAppleEventManager sharedAppleEventManager] setEventHandler:[RCTLinkingManager class]
                                                     andSelector:@selector(getUrlEventHandler:withReplyEvent:)
                                                   forEventClass:kInternetEventClass

Changelog

[macOS] [Added] - Provide option to not blindly foreground app's lastWindow from deepLinks

Test Plan

Using js/examples/Linking/LinkingExample.js I simply added an eventListener

Linking.addEventListener('url', url => console.log(url));

as otherwise the LinkingManager.mm does not observe:
https://github.com/microsoft/react-native-macos/blob/main/Libraries/LinkingIOS/macos/RCTLinkingManager.mm#L44

https://github.com/microsoft/react-native-macos/blob/main/React/Modules/RCTEventEmitter.m#L115

Disable alwaysForegroundLastWindow

dontF.mov

Current behavior, always foreground

Fore.mov