Unpin webview_flutter_wkwebview once google_mobile_ads raises its minimum iOS version to 15 #194871

#194864 pinned webview_flutter_wkwebview to 3.27.0 in kManuallyPinnedDependencies to unblock the tree.

webview_flutter_wkwebview 3.27.1 (flutter/packages#13294) raised its Swift package floor to iOS 15. google_mobile_ads still declares iOS 13 and depends on the webview-flutter-wkwebview product, so SwiftPM refuses to build any app that has both:

Target Integrity (Xcode): The package product 'webview-flutter-wkwebview' requires minimum platform version 15.0 for the iOS platform, but this target supports 13.0 (in target 'google_mobile_ads' from project 'google_mobile_ads')

dev/benchmarks/platform_views_layout depends on google_mobile_ads, which is why the four Mac_ios platform_views_scroll_perf_* builders went red after #194819 (e.g. https://ci.chromium.org/b/8667465549370430577). The same failure hits any user app that uses google_mobile_ads with SwiftPM once pub resolves webview_flutter_wkwebview to 3.27.1; google_mobile_ads 9.1.0 (latest) has the same iOS 13 floor.

To close this issue:

• google_mobile_ads releases a version whose Package.swift declares iOS 15 or higher.
• Remove the webview_flutter_wkwebview entry from kManuallyPinnedDependencies in packages/flutter_tools/lib/src/update_packages_pins.dart and run flutter update-packages --force-upgrade.