Snapshot DDC trained on itself

pkg/dev_compiler/lib/src/compiler/code_generator.dart

Index: pkg/dev_compiler/lib/src/compiler/code_generator.dart
diff --git a/pkg/dev_compiler/lib/src/compiler/code_generator.dart b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
index 5866870795b4c6b7889adaf99ac693c3d05011d2..9843eb0b3be33f42817b135b573bae128b498e44 100644
--- a/pkg/dev_compiler/lib/src/compiler/code_generator.dart
+++ b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
@@ -33,7 +33,7 @@ import 'package:analyzer/src/summary/summarize_elements.dart'
 import 'package:analyzer/src/summary/summary_sdk.dart';
 import 'package:analyzer/src/task/strong/ast_properties.dart'
     show isDynamicInvoke, setIsDynamicInvoke, getImplicitAssignmentCast;
-import 'package:path/path.dart' show relative, separator;
+import 'package:path/path.dart' show isWithin, relative, separator;
 
 import '../closure/closure_annotator.dart' show ClosureAnnotator;
 import '../js_ast/js_ast.dart' as JS;
@@ -6032,7 +6032,7 @@ String jsLibraryName(String libraryRoot, LibraryElement library) {
     // TODO(vsm): This is not unique if an escaped '/'appears in a filename.
     // E.g., "foo/bar.dart" and "foo$47bar.dart" would collide.
     qualifiedPath = uri.pathSegments.skip(1).join(encodedSeparator);
-  } else if (uri.toFilePath().startsWith(libraryRoot)) {
+  } else if (isWithin(libraryRoot, uri.toFilePath())) {
     qualifiedPath = uri.path
         .substring(libraryRoot.length)
         .replaceAll(separator, encodedSeparator);
@@ -6051,7 +6051,7 @@ String jsLibraryDebuggerName(String libraryRoot, LibraryElement library) {
   if (uri.scheme == 'dart' || uri.scheme == 'package') return uri.toString();
 
   var filePath = uri.toFilePath();
-  if (!filePath.startsWith(libraryRoot)) {
+  if (!isWithin(libraryRoot, filePath)) {
     throw 'Invalid library root. $libraryRoot does not contain ${uri
         .toFilePath()}';
   }