Support serialization of generic methods.

pkg/compiler/lib/src/serialization/type_serialization.dart

Index: pkg/compiler/lib/src/serialization/type_serialization.dart
diff --git a/pkg/compiler/lib/src/serialization/type_serialization.dart b/pkg/compiler/lib/src/serialization/type_serialization.dart
index 24a46ae27f84757df04aac019727a6bd9b99f8e5..ed94ade3e780460047b23db8bf6e1e5495bb36bf 100644
--- a/pkg/compiler/lib/src/serialization/type_serialization.dart
+++ b/pkg/compiler/lib/src/serialization/type_serialization.dart
@@ -5,6 +5,7 @@
 library dart2js.serialization.types;
 
 import '../dart_types.dart';
+import '../elements/elements.dart';
 import 'serialization.dart';
 import 'keys.dart';
 
@@ -24,6 +25,8 @@ class TypeSerializer extends DartTypeVisitor<dynamic, ObjectEncoder> {
 
   void visitTypeVariableType(TypeVariableType type, ObjectEncoder encoder) {
     encoder.setElement(Key.ELEMENT, type.element);
+    encoder.setBool(
+        Key.IS_METHOD_TYPE_VARIABLE_TYPE, type is MethodTypeVariableType);
   }
 
   void visitFunctionType(FunctionType type, ObjectEncoder encoder) {
@@ -76,7 +79,11 @@ class TypeDeserializer {
             decoder.getStrings(Key.NAMED_PARAMETERS, isOptional: true),
             decoder.getTypes(Key.NAMED_PARAMETER_TYPES, isOptional: true));
       case TypeKind.TYPE_VARIABLE:
-        return new TypeVariableType(decoder.getElement(Key.ELEMENT));
+        TypeVariableElement element = decoder.getElement(Key.ELEMENT);
+        if (decoder.getBool(Key.IS_METHOD_TYPE_VARIABLE_TYPE)) {
+          return new MethodTypeVariableType(element);
+        }
+        return new TypeVariableType(element);
       case TypeKind.TYPEDEF:
         return new TypedefType(decoder.getElement(Key.ELEMENT),
             decoder.getTypes(Key.TYPE_ARGUMENTS, isOptional: true));