Don't tag fromEnvironment constructors as native

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

Index: pkg/compiler/lib/src/native/native.dart
diff --git a/pkg/compiler/lib/src/native/native.dart b/pkg/compiler/lib/src/native/native.dart
index cba55120ca83194b867f7d9710f3cb3b4695cb21..1d68d7a0bf9edd97a1899b89e8e125d809f0874b 100644
--- a/pkg/compiler/lib/src/native/native.dart
+++ b/pkg/compiler/lib/src/native/native.dart
@@ -4,9 +4,6 @@
 
 library native;
 
-import '../compiler.dart' show Compiler;
-import '../elements/entities.dart';
-
 export 'behavior.dart';
 export 'enqueue.dart';
 export 'js.dart';
@@ -27,21 +24,17 @@ const Iterable<String> _allowedDartSchemePaths = const <String>[
   'web_sql'
 ];
 
-bool maybeEnableNative(Compiler compiler, LibraryEntity library) {
+bool maybeEnableNative(Uri uri, {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;
 }