[FirebaseMessaging] Fix crash on Xcode 26 + iOS 18

[subdiox]

Summary

Fixes a crash that occurs when launching an app linked with FirebaseMessaging and FirebaseInAppMessaging on iOS 18 devices or simulators when built with Xcode 26 Beta 4.

Root Cause

The crash was caused by referencing the symbol NSUserActivityTypeBrowsingWeb, which appears to be unavailable or unresolved at runtime when using the combination of Xcode 26 and iOS 18. Attempting to access this symbol directly results in a dyld crash:

dyld[27074]: Symbol not found: _NSUserActivityTypeBrowsingWeb
  Referenced from: <7CB71490-F307-3C6E-853C-925749317C78> /private/var/containers/Bundle/Application/C7665515-F4B5-4EAA-B560-774A439A4F1E/Rulebook-Dev.app/Rulebook-Dev.debug.dylib
  Expected in:     <050203DD-7488-307D-A999-E587314B041A> /System/Library/Frameworks/CoreServices.framework/CoreServices
Symbol not found: _NSUserActivityTypeBrowsingWeb
  Referenced from: <7CB71490-F307-3C6E-853C-925749317C78> /private/var/containers/Bundle/Application/C7665515-F4B5-4EAA-B560-774A439A4F1E/Rulebook-Dev.app/Rulebook-Dev.debug.dylib
  Expected in:     <050203DD-7488-307D-A999-E587314B041A> /System/Library/Frameworks/CoreServices.framework/CoreServices
dyld config: DYLD_LIBRARY_PATH=/usr/lib/system/introspection DYLD_INSERT_LIBRARIES=/usr/lib/libLogRedirect.dylib:/usr/lib/libBacktraceRecording.dylib:/usr/lib/libMainThreadChecker.dylib:/usr/lib/libRPAC.dylib:/usr/lib/libViewDebuggerSupport.dylib
Symbol not found: _NSUserActivityTypeBrowsingWeb
  Referenced from: <7CB71490-F307-3C6E-853C-925749317C78> /private/var/containers/Bundle/Application/C7665515-F4B5-4EAA-B560-774A439A4F1E/Rulebook-Dev.app/Rulebook-Dev.debug.dylib
  Expected in:     <050203DD-7488-307D-A999-E587314B041A> /System/Library/Frameworks/CoreServices.framework/CoreServices
dyld config: DYLD_LIBRARY_PATH=/usr/lib/system/introspection DYLD_INSERT_LIBRARIES=/usr/lib/libLogRedirect.dylib:/usr/lib/libBacktraceRecording.dylib:/usr/lib/libMainThreadChecker.dylib:/usr/lib/libRPAC.dylib:/usr/lib/libViewDebuggerSupport.dylib

Fix

Replaced the symbol reference with a raw string literal @"NSUserActivityTypeBrowsingWeb", which avoids the runtime lookup and resolves the crash.

Related Issue

This issue is discussed in #15159.

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[ncooke3]

Clever fix, thank you!

[ncooke3]

Could you please run the style script?

scripts/style.sh FirebaseInAppMessaging/Sources/Runtime/FIRIAMActionURLFollower.m FirebaseInAppMessaging/Tests/Unit/FIRIAMActionUrlFollowerTests.m FirebaseMessaging/Sources/FIRMessaging.m

[ncooke3]

Also, please prepend the FirebaseMessaging/CHANGELOG.md with a brief release note. Example:

# 12.1.0
- [fixed] Fix Xcode 26 crash from missing `NSUserActivityTypeBrowsingWeb` symbol. (#15159)