Revert "Make PbMapMixin implement Map<String, dynamic>"

We don't have a way to put type parameters on a mixin,
so we can't do this yet.

This reverts commit 97e5bb7.

BUG=
R=kevmoo@google.com

Review URL: https://codereview.chromium.org//2055973002 .

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.5.1+5
+
+* Revert previous change because it causes strong mode type error
+in the generated code. We will revisit this in a new version of
+mixin support.
+
 ## 0.5.1+4
 
 * Use a more refined implementation of `Map` in `PbMapMixin`

lib/src/protobuf/mixins/map_mixin.dart

@@ -11,7 +11,7 @@ import "package:protobuf/protobuf.dart" show BuilderInfo;
 ///
 /// This mixin is enabled via an option in
 /// dart_options.proto in dart-protoc-plugin.
-abstract class PbMapMixin implements Map<String, dynamic> {
+abstract class PbMapMixin implements Map {
   // GeneratedMessage properties and methods used by this mixin.
 
   BuilderInfo get info_;
@@ -29,8 +29,8 @@ abstract class PbMapMixin implements Map<String, dynamic> {
   }
 
   @override
-  void operator []=(String key, val) {
-    var tag = getTagNumber(key);
+  operator []=(key, val) {
+    var tag = getTagNumber(key as String);
     if (tag == null) {
       throw new ArgumentError(
           "field '${key}' not found in ${info_.messageName}");
@@ -39,13 +39,13 @@ abstract class PbMapMixin implements Map<String, dynamic> {
   }
 
   @override
-  Iterable<String> get keys => info_.byName.keys;
+  get keys => info_.byName.keys;
 
   @override
   bool containsKey(Object key) => info_.byName.containsKey(key);
 
   @override
-  int get length => info_.byName.length;
+  get length => info_.byName.length;
 
   @override
   remove(key) {

pubspec.yaml

@@ -1,5 +1,5 @@
 name: protobuf
-version: 0.5.1+4
+version: 0.5.1+5
 author: Dart Team <misc@dartlang.org>
 description: Runtime library for protobuf support.
 homepage: https://github.com/dart-lang/dart-protobuf

test/map_mixin_test.dart

@@ -15,7 +15,7 @@ import 'package:test/test.dart' show test, expect, same, throws;
 import 'mock_util.dart' show MockMessage, mockInfo;
 
 // A minimal protobuf implementation compatible with PbMapMixin.
-class Rec extends MockMessage with MapMixin<String, dynamic>, PbMapMixin {
+class Rec extends MockMessage with MapMixin, PbMapMixin {
   get info_ => _info;
   static final _info = mockInfo("Rec", () => new Rec());