Move enableNative to target, turn it on by default

pkg/compiler/lib/src/kernel/fasta_support.dart

 // Copyright (c) 2017, 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.
 
 /// Additions to Fasta for generating .dill (Kernel IR) files with dart2js patch
 /// files and native hooks.
 library compiler.src.kernel.fasta_support;
 
 // TODO(sigmund): get rid of this file. Fasta should be agnostic of the
 // target platform, at which point this should not be necessary. In particular,
@@ skipping 11 matching lines @@
 import 'package:front_end/src/fasta/kernel/utils.dart';
 import 'package:kernel/ast.dart' show Source;
 
 import 'package:front_end/src/fasta/compiler_context.dart' show CompilerContext;
 import 'package:front_end/src/fasta/dill/dill_target.dart' show DillTarget;
 import 'package:front_end/src/fasta/fasta.dart' show CompileTask;
 import 'package:front_end/src/fasta/kernel/kernel_target.dart'
     show KernelTarget;
 import 'package:front_end/src/fasta/loader.dart' show Loader;
 import 'package:front_end/src/fasta/parser/parser.dart' show optional;
+import 'package:front_end/src/fasta/source/source_library_builder.dart'
+    show SourceLibraryBuilder;
 import 'package:front_end/src/scanner/token.dart' show Token;
 import 'package:front_end/src/fasta/ticker.dart' show Ticker;
 import 'package:front_end/src/fasta/translate_uri.dart' show TranslateUri;
 
 /// Generates a platform.dill file containing the compiled Kernel IR of the
 /// dart2js SDK.
 Future compilePlatform(Uri patchedSdk, Uri fullOutput,
     {Uri outlineOutput, Uri packages}) async {
   Uri deps = Uri.base.resolveUri(new Uri.file("${fullOutput.toFilePath()}.d"));
   TranslateUri uriTranslator = await TranslateUri
@@ skipping 38 matching lines @@
 /// are run, JS-specific libraries are included in the SDK, and native clauses
 /// have no string parameter.
 class KernelTargetForDart2js extends KernelTarget {
   KernelTargetForDart2js(
       DillTarget target, TranslateUri uriTranslator, bool strongMode,
       [Map<String, Source> uriToSource])
       : super(PhysicalFileSystem.instance, target, uriTranslator, strongMode,
             uriToSource);
 
   @override
+  bool enableNative(SourceLibraryBuilder library) =>
+      library.uri.scheme == "dart" || library.isPatch;
+
+  @override
   Token skipNativeClause(Token token) => _skipNative(token);
 
   @override
   String extractNativeMethodName(Token token) => null;
 
   @override
   void loadExtraRequiredLibraries(Loader loader) => _loadExtras(loader);
 
   @override
   void runBuildTransformations() {}
@@ skipping 55 matching lines @@
   'dart:html_common',
   'dart:indexed_db',
   'dart:js',
   'dart:js_util',
   'dart:mirrors',
   'dart:svg',
   'dart:web_audio',
   'dart:web_gl',
   'dart:web_sql',
 ];