Read SDK and patches from a JSON file.

pkg/front_end/lib/src/fasta/source/outline_builder.dart

 // Copyright (c) 2016, 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 fasta.outline_builder;
 
 import 'package:kernel/ast.dart' show ProcedureKind;
 
 import '../fasta_codes.dart' show FastaMessage, codeExpectedBlockToSkip;
 
@@ skipping 30 matching lines @@
 
 enum MethodBody {
   Abstract,
   Regular,
   RedirectingFactoryBody,
 }
 
 class OutlineBuilder extends UnhandledListener {
   final SourceLibraryBuilder library;
 
-  final bool isDartLibrary;
+  final bool enableNative;
 
   String nativeMethodName;
 
   OutlineBuilder(SourceLibraryBuilder library)
       : library = library,
-        isDartLibrary = library.uri.scheme == "dart";
+        enableNative = (library.uri.scheme == "dart" || library.isPatch);
 
   @override
   Uri get uri => library.fileUri;
 
   @override
   int popCharOffset() => pop();
 
   List<String> popIdentifierList(int count) {
     if (count == 0) return null;
     List<String> list = new List<String>.filled(count, null, growable: true);
@@ skipping 701 matching lines @@
   }
 
   @override
   void handleModifiers(int count) {
     debugEvent("Modifiers");
     push(popList(count) ?? NullValue.Modifiers);
   }
 
   @override
   Token handleUnrecoverableError(Token token, FastaMessage message) {
-    if (isDartLibrary && message.code == codeExpectedBlockToSkip) {
+    if (enableNative && message.code == codeExpectedBlockToSkip) {
       var target = library.loader.target;
       Token recover = target.skipNativeClause(token);
       if (recover != null) {
         nativeMethodName = target.extractNativeMethodName(token);
         return recover;
       }
     }
     return super.handleUnrecoverableError(token, message);
   }
 
   @override
   Link<Token> handleMemberName(Link<Token> identifiers) {
-    if (!isDartLibrary || identifiers.isEmpty) return identifiers;
+    if (!enableNative || identifiers.isEmpty) return identifiers;
     return removeNativeClause(identifiers);
   }
 
   @override
   void debugEvent(String name) {
     // printEvent(name);
   }
 }