[google_maps_flutter] Add color scheme support to app-facing package (#11280)

App-facing portion of #10471, incorporating review feedback and some other minor cleanup.

Fixes flutter/flutter#176445

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: stuartmorgan-g

packages/google_maps_flutter/google_maps_flutter/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.16.0
+
+* Adds `colorScheme` support for web cloud-based maps styling brightness.
+
 ## 2.15.0
 
 * Adds support for advanced markers, and new example pages showing their usage.

packages/google_maps_flutter/google_maps_flutter/lib/google_maps_flutter.dart

@@ -41,6 +41,7 @@ export 'package:google_maps_flutter_platform_interface/google_maps_flutter_platf
         LatLng,
         LatLngBounds,
         MapBitmapScaling,
+        MapColorScheme,
         MapStyleException,
         MapType,
         Marker,

packages/google_maps_flutter/google_maps_flutter/lib/src/google_map.dart

@@ -144,6 +144,7 @@ class GoogleMap extends StatefulWidget {
     this.onTap,
     this.onLongPress,
     this.markerType = GoogleMapMarkerType.marker,
+    this.colorScheme,
     String? mapId,
     @Deprecated('cloudMapId is deprecated. Use mapId instead.')
     String? cloudMapId,
@@ -411,6 +412,14 @@ class GoogleMap extends StatefulWidget {
   /// may result in unexpected behavior.
   final GoogleMapMarkerType markerType;
 
+  /// Color scheme for the cloud-style map. Web only.
+  ///
+  /// The colorScheme option can only be set when the map is initialized;
+  /// setting this option after the map is created will have no effect.
+  ///
+  /// See https://developers.google.com/maps/documentation/javascript/mapcolorscheme for more details.
+  final MapColorScheme? colorScheme;
+
   /// Creates a [State] for this [GoogleMap].
   @override
   State createState() => _GoogleMapState();
@@ -767,6 +776,7 @@ MapConfiguration _configurationFromMapWidget(GoogleMap map) {
     trafficEnabled: map.trafficEnabled,
     buildingsEnabled: map.buildingsEnabled,
     markerType: mapConfigurationMarkerType,
+    colorScheme: map.colorScheme,
     // A null mapId in the widget means no map ID, which is expressed as '' in
     // the configuration to distinguish from no change (null).
     mapId: map.mapId ?? '',

packages/google_maps_flutter/google_maps_flutter/pubspec.yaml

@@ -2,7 +2,7 @@ name: google_maps_flutter
 description: A Flutter plugin for integrating Google Maps in iOS and Android applications.
 repository: https://github.com/flutter/packages/tree/main/packages/google_maps_flutter/google_maps_flutter
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+maps%22
-version: 2.15.0
+version: 2.16.0
 
 environment:
   sdk: ^3.10.0
@@ -23,8 +23,8 @@ dependencies:
     sdk: flutter
   google_maps_flutter_android: ^2.19.1
   google_maps_flutter_ios: ^2.18.0
-  google_maps_flutter_platform_interface: ^2.14.2
-  google_maps_flutter_web: ^0.6.1
+  google_maps_flutter_platform_interface: ^2.15.0
+  google_maps_flutter_web: ^0.6.2
 
 dev_dependencies:
   flutter_test:

packages/google_maps_flutter/google_maps_flutter/test/google_map_test.dart

@@ -711,6 +711,39 @@ void main() {
     expect(map.mapConfiguration.markerType, MarkerType.marker);
   });
 
+  testWidgets('Is default color scheme null', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: GoogleMap(
+          initialCameraPosition: CameraPosition(target: LatLng(10.0, 15.0)),
+        ),
+      ),
+    );
+
+    final PlatformMapStateRecorder map = platform.lastCreatedMap;
+
+    expect(map.mapConfiguration.colorScheme, null);
+  });
+
+  testWidgets('Can set color scheme to non-default', (
+    WidgetTester tester,
+  ) async {
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: GoogleMap(
+          initialCameraPosition: CameraPosition(target: LatLng(10.0, 15.0)),
+          colorScheme: MapColorScheme.light,
+        ),
+      ),
+    );
+
+    final PlatformMapStateRecorder map = platform.lastCreatedMap;
+
+    expect(map.mapConfiguration.colorScheme, MapColorScheme.light);
+  });
+
   testWidgets('Can update mapId', (WidgetTester tester) async {
     await tester.pumpWidget(
       const Directionality(