flutter.gradle: collect list of Android plugins from .flutter-plugins-dependencies (#59294)

packages/flutter_tools/gradle/flutter.gradle

@@ -372,17 +372,27 @@ class FlutterPlugin implements Plugin<Project> {
     }
 
     private Properties getPluginList() {
-        File pluginsFile = new File(project.projectDir.parentFile.parentFile, '.flutter-plugins')
-        Properties allPlugins = readPropertiesIfExist(pluginsFile)
         Properties androidPlugins = new Properties()
-        allPlugins.each { name, path ->
-            if (doesSupportAndroidPlatform(path)) {
-                androidPlugins.setProperty(name, path)
+
+        def flutterProjectRoot = project.projectDir.parentFile.parentFile
+        def pluginsFile = new File(flutterProjectRoot, '.flutter-plugins-dependencies')
+        if (!pluginsFile.exists()) {
+            return androidPlugins
         }
-            // TODO(amirh): log an error if this plugin was specified to be an Android
-            // plugin according to the new schema, and was missing a build.gradle file.
-            // https://github.com/flutter/flutter/issues/40784
+
+        def object = new JsonSlurper().parseText(pluginsFile.text)
+        assert object instanceof Map
+        assert object.plugins instanceof Map
+        assert object.plugins.android instanceof List
+        // Includes the Flutter plugins that support the Android platform.
+        object.plugins.android.each { androidPlugin ->
+            assert androidPlugin.name instanceof String
+            assert androidPlugin.path instanceof String
+            def pluginDirectory = new File(androidPlugin.path, 'android')
+            assert pluginDirectory.exists()
+            androidPlugins.setProperty(androidPlugin.name, androidPlugin.path)
         }
+
         return androidPlugins
     }