fix #27784 and fix #27785, fromEnvironment constants in DDC

pkg/dev_compiler/tool/patch_sdk.dart

 #!/usr/bin/env 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.
 
 /// Command line tool to merge the SDK libraries and our patch files.
 /// This is currently designed as an offline tool, but we could automate it.
 
 import 'dart:io';
 import 'dart:math' as math;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:path/path.dart' as path;
 
 void main(List<String> argv) {
+  var self = path.relative(path.fromUri(Platform.script));
   if (argv.length < 2) {
-    var self = path.relative(path.fromUri(Platform.script));
     var toolDir = path.relative(path.dirname(path.fromUri(Platform.script)));
 
     var inputExample = path.join(toolDir, 'input_sdk');
     var outExample =
         path.relative(path.normalize(path.join('gen', 'patched_sdk')));
 
     print('Usage: $self INPUT_DIR OUTPUT_DIR');
     print('For example:');
     print('\$ $self $inputExample $outExample');
     exit(1);
   }
 
+  var selfModifyTime = new File(self).lastModifiedSync().millisecondsSinceEpoch;
+
   var input = argv[0];
   var sdkLibIn = path.join(input, 'lib');
   var patchIn = path.join(input, 'patch');
   var privateIn = path.join(input, 'private');
   var sdkOut = path.join(argv[1], 'lib');
 
   var INTERNAL_PATH = '_internal/compiler/js_lib/';
 
   // Copy libraries.dart and version
   var libContents = new File(path.join(sdkLibIn, '_internal', 'libraries.dart'))
@@ skipping 23 matching lines @@
           path.join(privateIn, library.path.replaceAll(INTERNAL_PATH, ''));
     } else {
       libraryIn = libraryOut;
     }
 
     var libraryFile = new File(libraryIn);
     if (libraryFile.existsSync()) {
       var outPaths = <String>[libraryOut];
       var libraryContents = libraryFile.readAsStringSync();
 
-      int inputModifyTime =
-          libraryFile.lastModifiedSync().millisecondsSinceEpoch;
+      int inputModifyTime = math.max(selfModifyTime,
+          libraryFile.lastModifiedSync().millisecondsSinceEpoch);
       var partFiles = <File>[];
       for (var part in parseDirectives(libraryContents).directives) {
         if (part is PartDirective) {
           var partPath = part.uri.stringValue;
           outPaths.add(path.join(path.dirname(libraryOut), partPath));
 
           var partFile = new File(path.join(path.dirname(libraryIn), partPath));
           partFiles.add(partFile);
           inputModifyTime = math.max(inputModifyTime,
               partFile.lastModifiedSync().millisecondsSinceEpoch);
@@ skipping 170 matching lines @@
     var patchNode = patch.patches[name];
     if (patchNode == null) {
       print('warning: patch not found for $name: $node');
       return;
     }
 
     Annotation patchMeta = patchNode.metadata.lastWhere(_isPatchAnnotation);
     int start = patchMeta.endToken.next.offset;
     var code = patch.contents.substring(start, patchNode.end);
 
+    // Const factory constructors can't be legally parsed from the patch file,
+    // so we need to omit the "const" there, but still preserve it.
+    if (node is ConstructorDeclaration &&
+        node.constKeyword != null &&
+        patchNode is ConstructorDeclaration &&
+        patchNode.constKeyword == null) {
+      code = 'const $code';
+    }
+
     // For some node like static fields, the node's offset doesn't include
     // the external keyword. Also starting from the keyword lets us preserve
     // documentation comments.
     edits.replace(externalKeyword.offset, node.end, code);
   }
 }
 
 class PatchFinder extends GeneralizingAstVisitor {
   final String contents;
   final CompilationUnit unit;
@@ skipping 151 matching lines @@
     if (diff != 0) return diff;
     return end - other.end;
   }
 }
 
 List<SdkLibrary> _getSdkLibraries(String contents) {
   var libraryBuilder = new SdkLibrariesReader_LibraryBuilder(true);
   parseCompilationUnit(contents).accept(libraryBuilder);
   return libraryBuilder.librariesMap.sdkLibraries;
 }