[google_maps_flutter_ios] Adds Swift Package Manager compatibility

[vashworth]

Makes google_maps_flutter_ios available as a Swift Package to Flutter. Also, remains compatible with CocoaPods.

Fixes flutter/flutter#146920.

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages repo does use dart format.)
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is exempt from version changes.
• I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[vashworth]

Using GoogleMaps Swift Package appears to be having issues:

https://ci.chromium.org/ui/p/flutter/builders/try/Mac_arm64%20ios_platform_tests_shard_2%20master/12829/overview
Fails on 'build examples'

BUILDING google_maps_flutter/google_maps_flutter_ios/example/ios14 for iOS
 Running command: "flutter build ios --no-codesign" in /Volumes/Work/s/w/ir/x/w/packages/packages/google_maps_flutter/google_maps_flutter_ios/example/ios14
 Warning: Building for device with codesigning disabled. You will have to manually codesign before deploying to device.
 Building dev.flutter.plugins.googleMobileMapsExample for device (ios-release)...
 ...
 Running pod install...                                           1,133ms
 Running Xcode build...                                          
 Xcode build done.                                            8.5s
 Failed to build iOS app
 Parse Issue (Xcode): Module 'GoogleMaps' not found
 /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Core/GMSEmpty.m:16:8
 Encountered error while building for device.

https://ci.chromium.org/ui/p/flutter/builders/try/Mac_arm64%20ios_platform_tests_shard_1%20master/12751/overview
Fails on 'drive examples'

Running command: "flutter test -d 0E012867-5DC0-45CC-8AA7-E26E8D5B816D integration_test" in /Volumes/Work/s/w/ir/x/w/packages/packages/google_maps_flutter/google_maps_flutter_ios/example/ios14
...
Running Xcode build...                                                                           
Xcode build done.                                            6.8s
Failed to build iOS app
Parse Issue (Xcode): Module 'GoogleMaps' not found
/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Core/GMSEmpty.m:16:8
Could not build the application for the simulator.

Does not happen every time

[vashworth]

https://ci.chromium.org/ui/p/flutter/builders/try/Mac_arm64%20ios_platform_tests_shard_2%20master/12830/overview

Error with verbose logs:

CompileC /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsCoreTarget.build/Objects-normal/arm64/GMSEmpty.o /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Core/GMSEmpty.m normal arm64 objective-c com.apple.compilers.llvm.clang.1_0.compiler (in target 'GoogleMapsCoreTarget' from project 'GoogleMaps')
                cd /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk
                /Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -x objective-c -ivfsstatcache /Users/chrome-bot/Library/Developer/Xcode/DerivedData/SDKStatCaches.noindex/iphonesimulator17.0-21A325-082b46144e8a3fe0e600305fde315d51.sdkstatcache -target arm64-apple-ios14.0-simulator -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -fobjc-arc -fmodules -gmodules -fmodules-cache-path\=/Users/chrome-bot/Library/Developer/Xcode/DerivedData/ModuleCache.noindex -fmodules-prune-interval\=86400 -fmodules-prune-after\=345600 -fbuild-session-file\=/Users/chrome-bot/Library/Developer/Xcode/DerivedData/ModuleCache.noindex/Session.modulevalidation -fmodules-validate-once-per-build-session -Wnon-modular-include-in-framework-module -Werror\=non-modular-include-in-framework-module -fmodule-name\=GoogleMapsCoreTarget -Wno-trigraphs -fpascal-strings -O0 -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-implicit-atomic-properties -Wno-objc-interface-ivars -Wno-arc-repeated-use-of-weak -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wno-unused-variable -Wunused-value -Wno-empty-body -Wno-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-constant-conversion -Wno-int-conversion -Wno-bool-conversion -Wno-enum-conversion -Wno-float-conversion -Wno-non-literal-null-conversion -Wno-objc-literal-conversion -Wshorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -Wno-implicit-fallthrough -DSWIFT_PACKAGE -DDEBUG\=1 -DOBJC_OLD_DISPATCH_PROTOTYPES\=1 -isysroot /Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator17.0.sdk -fstrict-aliasing -Wprotocol -Wdeprecated-declarations -g -Wno-sign-conversion -Wno-infinite-recursion -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-semicolon-before-method-body -fobjc-abi-version\=2 -fobjc-legacy-dispatch -I/Volumes/Work/s/w/ir/x/w/packages/packages/google_maps_flutter/google_maps_flutter_ios/example/ios14/build/ios/Debug-iphonesimulator/include -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Core/Sources -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsCoreTarget.build/DerivedSources-normal/arm64 -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsCoreTarget.build/DerivedSources/arm64 -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsCoreTarget.build/DerivedSources -F/Volumes/Work/s/w/ir/x/w/packages/packages/google_maps_flutter/google_maps_flutter_ios/example/ios14/build/ios/Debug-iphonesimulator -F/Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Frameworks -iframework /Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator17.0.sdk/Developer/Library/Frameworks -DXcode -MMD -MT dependencies -MF /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsCoreTarget.build/Objects-normal/arm64/GMSEmpty.d --serialize-diagnostics /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsCoreTarget.build/Objects-normal/arm64/GMSEmpty.dia -c /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Core/GMSEmpty.m -o /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsCoreTarget.build/Objects-normal/arm64/GMSEmpty.o
            /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Core/GMSEmpty.m:17:9: fatal error: module 'GoogleMaps' not found
            @import GoogleMaps;
             ~~~~~~~^~~~~~~~~~
            1 error generated.
            CompileC /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsBaseTarget.build/Objects-normal/arm64/GMSEmpty.o /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Base/GMSEmpty.m normal arm64 objective-c com.apple.compilers.llvm.clang.1_0.compiler (in target 'GoogleMapsBaseTarget' from project 'GoogleMaps')
                cd /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk
                /Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -x objective-c -ivfsstatcache /Users/chrome-bot/Library/Developer/Xcode/DerivedData/SDKStatCaches.noindex/iphonesimulator17.0-21A325-082b46144e8a3fe0e600305fde315d51.sdkstatcache -target arm64-apple-ios14.0-simulator -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -fobjc-arc -fmodules -gmodules -fmodules-cache-path\=/Users/chrome-bot/Library/Developer/Xcode/DerivedData/ModuleCache.noindex -fmodules-prune-interval\=86400 -fmodules-prune-after\=345600 -fbuild-session-file\=/Users/chrome-bot/Library/Developer/Xcode/DerivedData/ModuleCache.noindex/Session.modulevalidation -fmodules-validate-once-per-build-session -Wnon-modular-include-in-framework-module -Werror\=non-modular-include-in-framework-module -fmodule-name\=GoogleMapsBaseTarget -Wno-trigraphs -fpascal-strings -O0 -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-implicit-atomic-properties -Wno-objc-interface-ivars -Wno-arc-repeated-use-of-weak -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wno-unused-variable -Wunused-value -Wno-empty-body -Wno-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-constant-conversion -Wno-int-conversion -Wno-bool-conversion -Wno-enum-conversion -Wno-float-conversion -Wno-non-literal-null-conversion -Wno-objc-literal-conversion -Wshorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -Wno-implicit-fallthrough -DSWIFT_PACKAGE -DDEBUG\=1 -DOBJC_OLD_DISPATCH_PROTOTYPES\=1 -isysroot /Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator17.0.sdk -fstrict-aliasing -Wprotocol -Wdeprecated-declarations -g -Wno-sign-conversion -Wno-infinite-recursion -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-semicolon-before-method-body -fobjc-abi-version\=2 -fobjc-legacy-dispatch -I/Volumes/Work/s/w/ir/x/w/packages/packages/google_maps_flutter/google_maps_flutter_ios/example/ios14/build/ios/Debug-iphonesimulator/include -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Base/Sources -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsBaseTarget.build/DerivedSources-normal/arm64 -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsBaseTarget.build/DerivedSources/arm64 -I/Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsBaseTarget.build/DerivedSources -F/Volumes/Work/s/w/ir/x/w/packages/packages/google_maps_flutter/google_maps_flutter_ios/example/ios14/build/ios/Debug-iphonesimulator -F/Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Frameworks -iframework /Volumes/Work/s/w/ir/cache/osx_sdk/xcode_15a240d/XCode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator17.0.sdk/Developer/Library/Frameworks -DXcode -MMD -MT dependencies -MF /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsBaseTarget.build/Objects-normal/arm64/GMSEmpty.d --serialize-diagnostics /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsBaseTarget.build/Objects-normal/arm64/GMSEmpty.dia -c /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Base/GMSEmpty.m -o /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/Build/Intermediates.noindex/GoogleMaps.build/Debug-iphonesimulator/GoogleMapsBaseTarget.build/Objects-normal/arm64/GMSEmpty.o
            /Users/chrome-bot/Library/Developer/Xcode/DerivedData/Runner-bynswbqjzzfjuuheqrjysabjmvyt/SourcePackages/checkouts/ios-maps-sdk/Base/GMSEmpty.m:17:9: fatal error: module 'GoogleMaps' not found
            @import GoogleMaps;
             ~~~~~~~^~~~~~~~~~
            1 error generated.

[vashworth]

I believe this is an issue with https://github.com/googlemaps/ios-maps-sdk, added comment to existing issue: https://github.com/googlemaps/ios-maps-sdk/issues/10#issuecomment-2096890239

[vashworth]

Closing until GoogleMaps issue is resolved.