fix: make window.flashFrame(bool) flash continuously on macOS (#41391)

fix: window.flashFrame to flash continuously on mac

This brings the behavior to parity with Windows and Linux. Prior behavior: The first `flashFrame(true)` bounces the dock icon only once (using the [NSInformationalRequest](https://developer.apple.com/documentation/appkit/nsrequestuserattentiontype/nsinformationalrequest) level) and `flashFrame(false)` does nothing. New behavior: Flash continuously until `flashFrame(false)` is called. This uses the [NSCriticalRequest](https://developer.apple.com/documentation/appkit/nsrequestuserattentiontype/nscriticalrequest) level instead. To explicitly use `NSInformationalRequest` to cause a single dock icon bounce, it is still possible to use [`dock.bounce('informational')`](https://www.electronjs.org/docs/latest/api/dock#dockbouncetype-macos).

docs/breaking-changes.md

@@ -21,6 +21,10 @@ encoded data returned from this function now matches it.
 
 See [crbug.com/332584706](https://issues.chromium.org/issues/332584706) for more information.
 
+### Behavior Changed: `window.flashFrame(bool)` will flash dock icon continuously on macOS
+
+This brings the behavior to parity with Windows and Linux. Prior behavior: The first `flashFrame(true)` bounces the dock icon only once (using the [NSInformationalRequest](https://developer.apple.com/documentation/appkit/nsrequestuserattentiontype/nsinformationalrequest) level) and `flashFrame(false)` does nothing. New behavior: Flash continuously until `flashFrame(false)` is called. This uses the [NSCriticalRequest](https://developer.apple.com/documentation/appkit/nsrequestuserattentiontype/nscriticalrequest) level instead. To explicitly use `NSInformationalRequest` to cause a single dock icon bounce, it is still possible to use [`dock.bounce('informational')`](https://www.electronjs.org/docs/latest/api/dock#dockbouncetype-macos).
+
 ## Planned Breaking API Changes (30.0)
 
 ### Behavior Changed: cross-origin iframes now use Permission Policy to access features

shell/browser/native_window_mac.mm

@@ -1004,7 +1004,7 @@ std::string NativeWindowMac::GetTitle() const {
 
 void NativeWindowMac::FlashFrame(bool flash) {
   if (flash) {
-    attention_request_id_ = [NSApp requestUserAttention:NSInformationalRequest];
+    attention_request_id_ = [NSApp requestUserAttention:NSCriticalRequest];
   } else {
     [NSApp cancelUserAttentionRequest:attention_request_id_];
     attention_request_id_ = 0;