Don't tag fromEnvironment constructors as native

pkg/compiler/lib/src/native/native.dart

 // Copyright (c) 2012, 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 native;
 
-import '../compiler.dart' show Compiler;
 import '../elements/entities.dart';
 
 export 'behavior.dart';
 export 'enqueue.dart';
 export 'js.dart';
 export 'scanner.dart';
 export 'ssa.dart';
 
 const Iterable<String> _allowedDartSchemePaths = const <String>[
   'async',
   'html',
   'html_common',
   'indexed_db',
   'js',
   'js_util',
   'svg',
   '_native_typed_data',
   'web_audio',
   'web_gl',
   'web_sql'
 ];
 
-bool maybeEnableNative(Compiler compiler, LibraryEntity library) {
+bool maybeEnableNative(LibraryEntity library,

[Siggi Cherem (dart-lang), 2017/05/30 22:17:56]

Could we change this to just take the Uri instead?

I have a change in front-end/fasta in flight to make it more flexible about
where it allows the native keyword. Right now it only allows it within core
libs, but I'm changing it so we can override this in the dart2js target.

(see https://codereview.chromium.org/2913013003/ for details).

I now realize that once we want to use fasta in-memory (and not load just the
.dill file), then we'll likely need to have this exact logic as well. If we
switch the API to only expect a URI, then I can use it directly.

[Johnni Winther, 2017/05/31 08:40:01]

Done.

+    {bool allowNativeExtensions: false}) {
   bool allowedTestLibrary() {
     Uri uri = library.canonicalUri;
     String scriptName = uri.path;
     return scriptName.contains('sdk/tests/compiler/dart2js_native') ||
         scriptName.contains('sdk/tests/compiler/dart2js_extra');
   }
 
   bool allowedDartLibary() {
     Uri uri = library.canonicalUri;
     if (uri.scheme != 'dart') return false;
     return _allowedDartSchemePaths.contains(uri.path);
   }
 
-  return allowedTestLibrary() ||
-      allowedDartLibary() ||
-      compiler.options.allowNativeExtensions;
+  return allowedTestLibrary() || allowedDartLibary() || allowNativeExtensions;
 }