[google_maps_flutter] Move Android inspector to Pigeon (flutter#6958)

Converts the inspector API (only intended for use in integration tests) of the Android implementation to Pigeon. This is a small, simple API surface to start the migration with, allowing setting up the basic Pigeon plumbing without major changes.

Part of flutter#117907

packages/google_maps_flutter/google_maps_flutter_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.9.1
+
+* Converts inspector interface platform calls to Pigeon.
+
 ## 2.9.0
 
 * Adds support for BitmapDescriptor classes `AssetMapBitmap` and `BytesMapBitmap`.

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/ClusterManagersController.java

@@ -169,20 +169,16 @@ private static String getClusterManagerId(Object clusterManagerData) {
    * Requests all current clusters from the algorithm of the requested ClusterManager and converts
    * them to result response.
    */
-  public void getClustersWithClusterManagerId(
-      String clusterManagerId, MethodChannel.Result result) {
+  public @NonNull Set<? extends Cluster<MarkerBuilder>> getClustersWithClusterManagerId(
+      String clusterManagerId) {
     ClusterManager<MarkerBuilder> clusterManager = clusterManagerIdToManager.get(clusterManagerId);
     if (clusterManager == null) {
-      result.error(
+      throw new Messages.FlutterError(
           "Invalid clusterManagerId",
           "getClusters called with invalid clusterManagerId:" + clusterManagerId,
           null);
-      return;
     }
-
-    final Set<? extends Cluster<MarkerBuilder>> clusters =
-        clusterManager.getAlgorithm().getClusters(googleMap.getCameraPosition().zoom);
-    result.success(Convert.clustersToJson(clusterManagerId, clusters));
+    return clusterManager.getAlgorithm().getClusters(googleMap.getCameraPosition().zoom);
   }
 
   @Override

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/Convert.java

@@ -36,7 +36,6 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 /** Conversions between JSON-like values and GoogleMaps data types. */
 class Convert {
@@ -377,6 +376,13 @@ static Object latLngBoundsToJson(LatLngBounds latLngBounds) {
     return arguments;
   }
 
+  static Messages.PlatformLatLngBounds latLngBoundsToPigeon(LatLngBounds latLngBounds) {
+    return new Messages.PlatformLatLngBounds.Builder()
+        .setNortheast(latLngToPigeon(latLngBounds.northeast))
+        .setSouthwest(latLngToPigeon(latLngBounds.southwest))
+        .build();
+  }
+
   static Object markerIdToJson(String markerId) {
     if (markerId == null) {
       return null;
@@ -431,13 +437,11 @@ static Object latLngToJson(LatLng latLng) {
     return Arrays.asList(latLng.latitude, latLng.longitude);
   }
 
-  static Object clustersToJson(
-      String clusterManagerId, Set<? extends Cluster<MarkerBuilder>> clusters) {
-    List<Object> data = new ArrayList<>(clusters.size());
-    for (Cluster<MarkerBuilder> cluster : clusters) {
-      data.add(clusterToJson(clusterManagerId, cluster));
-    }
-    return data;
+  static Messages.PlatformLatLng latLngToPigeon(LatLng latLng) {
+    return new Messages.PlatformLatLng.Builder()
+        .setLat(latLng.latitude)
+        .setLng(latLng.longitude)
+        .build();
   }
 
   static Object clusterToJson(String clusterManagerId, Cluster<MarkerBuilder> cluster) {
@@ -470,6 +474,27 @@ static Object clusterToJson(String clusterManagerId, Cluster<MarkerBuilder> clus
     return data;
   }
 
+  static Messages.PlatformCluster clusterToPigeon(
+      String clusterManagerId, Cluster<MarkerBuilder> cluster) {
+    int clusterSize = cluster.getSize();
+    String[] markerIds = new String[clusterSize];
+    MarkerBuilder[] markerBuilders = cluster.getItems().toArray(new MarkerBuilder[clusterSize]);
+
+    LatLngBounds.Builder latLngBoundsBuilder = LatLngBounds.builder();
+    for (int i = 0; i < clusterSize; i++) {
+      MarkerBuilder markerBuilder = markerBuilders[i];
+      latLngBoundsBuilder.include(markerBuilder.getPosition());
+      markerIds[i] = markerBuilder.markerId();
+    }
+
+    return new Messages.PlatformCluster.Builder()
+        .setClusterManagerId(clusterManagerId)
+        .setPosition(latLngToPigeon(cluster.getPosition()))
+        .setBounds(latLngBoundsToPigeon(latLngBoundsBuilder.build()))
+        .setMarkerIds(Arrays.asList(markerIds))
+        .build();
+  }
+
   static LatLng toLatLng(Object o) {
     final List<?> data = toList(o);
     return new LatLng(toDouble(data.get(0)), toDouble(data.get(1)));