[pigeon] Removes the @protected annotation from the InstanceManager field of the PigeonInternalProxyApiBaseClass (flutter#8125)

It's common to access the `InstanceManager` when creating platform views, so this removes the `@protected` annotation to prevent lint warnings.

See flutter/packages#7794 (comment)

Author: bparrishMines

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 22.6.2
+
+* Removes the `@protected` annotation from the InstanceManager field of the
+  `PigeonInternalProxyApiBaseClass`.
+
 ## 22.6.1
 
 * [gobject] Moves class declarations to the header to work around a bug in some

packages/pigeon/lib/dart/templates.dart

@@ -255,7 +255,6 @@ abstract class $proxyApiBaseClassName {
   final BinaryMessenger? $_proxyApiBaseClassMessengerVarName;
 
   /// Maintains instances stored to communicate with native language objects.
-  @protected
   final $dartInstanceManagerClassName $_proxyApiBaseClassInstanceManagerVarName;
 
   /// Instantiates and returns a functionally identical object to oneself.

packages/pigeon/lib/generator_tools.dart

@@ -14,7 +14,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '22.6.1';
+const String pigeonVersion = '22.6.2';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/platform_tests/shared_test_plugin_code/lib/src/generated/proxy_api_tests.gen.dart

@@ -54,7 +54,6 @@ abstract class PigeonInternalProxyApiBaseClass {
   final BinaryMessenger? pigeon_binaryMessenger;
 
   /// Maintains instances stored to communicate with native language objects.
-  @protected
   final PigeonInstanceManager pigeon_instanceManager;
 
   /// Instantiates and returns a functionally identical object to oneself.

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 22.6.1 # This must match the version in lib/generator_tools.dart
+version: 22.6.2 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: ^3.3.0

packages/pigeon/test/dart/proxy_api_test.dart

@@ -177,6 +177,62 @@ void main() {
       );
     });
 
+    group('ProxyApi base class', () {
+      test('class name', () {
+        final Root root = Root(apis: <Api>[
+          AstProxyApi(
+            name: 'Api',
+            constructors: <Constructor>[],
+            fields: <ApiField>[],
+            methods: <Method>[],
+          )
+        ], classes: <Class>[], enums: <Enum>[]);
+        final StringBuffer sink = StringBuffer();
+        const DartGenerator generator = DartGenerator();
+        generator.generate(
+          const DartOptions(),
+          root,
+          sink,
+          dartPackageName: DEFAULT_PACKAGE_NAME,
+        );
+        final String code = sink.toString();
+
+        expect(
+          code,
+          contains(r'abstract class PigeonInternalProxyApiBaseClass'),
+        );
+      });
+
+      test('InstanceManager field', () {
+        final Root root = Root(apis: <Api>[
+          AstProxyApi(
+            name: 'Api',
+            constructors: <Constructor>[],
+            fields: <ApiField>[],
+            methods: <Method>[],
+          )
+        ], classes: <Class>[], enums: <Enum>[]);
+        final StringBuffer sink = StringBuffer();
+        const DartGenerator generator = DartGenerator();
+        generator.generate(
+          const DartOptions(),
+          root,
+          sink,
+          dartPackageName: DEFAULT_PACKAGE_NAME,
+        );
+        final String code = sink.toString();
+        final String collapsedCode = _collapseNewlineAndIndentation(code);
+
+        expect(
+          collapsedCode,
+          contains(
+            '/// Maintains instances stored to communicate with native language objects. '
+            'final PigeonInstanceManager pigeon_instanceManager;',
+          ),
+        );
+      });
+    });
+
     group('inheritance', () {
       test('extends', () {
         final AstProxyApi api2 = AstProxyApi(