Serialize and process patch metadata

tests/compiler/dart2js/serialization/equivalence_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.serialization_test;
 
 import 'dart:io';
 import '../memory_compiler.dart';
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/commandline_options.dart';
@@ skipping 269 matching lines @@
     check(element1, element2, 'isAbstract',
         element1.isAbstract, element2.isAbstract);
     check(element1, element2, 'isStatic',
         element1.isStatic, element2.isStatic);
     check(element1, element2, 'isTopLevel',
         element1.isTopLevel, element2.isTopLevel);
     check(element1, element2, 'isClassMember',
         element1.isClassMember, element2.isClassMember);
     check(element1, element2, 'isInstanceMember',
         element1.isInstanceMember, element2.isInstanceMember);
+    List<MetadataAnnotation> metadata1 = <MetadataAnnotation>[];
+    metadata1.addAll(element1.metadata);
+    if (element1.isPatched) {
+      metadata1.addAll(element1.implementation.metadata);
+    }
+    List<MetadataAnnotation> metadata2 = <MetadataAnnotation>[];
+    metadata2.addAll(element2.metadata);
+    if (element2.isPatched) {
+      metadata2.addAll(element2.implementation.metadata);
+    }
     checkListEquivalence(element1, element2, 'metadata',
-        element1.metadata, element2.metadata, checkMetadata);
+        metadata1, metadata2, checkMetadata);
   }
 
   @override
   void visitElement(Element e, Element arg) {
     throw new UnsupportedError("Unsupported element $e");
   }
 
   @override
   void visitLibraryElement(LibraryElement element1, LibraryElement element2) {
     checkElementIdentities(null, null, null, element1, element2);
@@ skipping 85 matching lines @@
         String message =
             'Missing member for $member1 in\n ${members2.join('\n ')}';
         if (member1.isAbstractField) {
           // TODO(johnniwinther): Ensure abstract fields are handled correctly.
           //print(message);
           continue;
         } else {
           throw message;
         }
       }
-      currentCheck = new Check(currentCheck, element1, element1,
+      currentCheck = new Check(currentCheck, element1, element2,
           'member:$name', member1, member2);
       visit(member1, member2);
       currentCheck = currentCheck.parent;
     }
   }
 
   @override
   void visitClassElement(ClassElement element1, ClassElement element2) {
     checkElementIdentities(null, null, null, element1, element2);
     check(element1, element2, 'name',
@@ skipping 378 matching lines @@
   void visitPrefixElement(PrefixElement element1, PrefixElement element2) {
     check(
         element1, element2, 'isDeferred',
         element1.isDeferred, element2.isDeferred);
     checkElementIdentities(
         element1, element2, 'importedLibrary',
         element1.deferredImport, element2.deferredImport);
     // TODO(johnniwinther): Check members.
   }
 }