Allow dev-compiler folder to have a different name, instead check the pubspec

lib/src/utils.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.
 
 /// Holds a couple utility functions used at various places in the system.
 library dev_compiler.src.utils;
 
 import 'dart:io';
 
 import 'package:path/path.dart' as path;
 import 'package:analyzer/src/generated/ast.dart'
     show
         ImportDirective,
         ExportDirective,
         PartDirective,
         CompilationUnit,
         Identifier,
         AnnotatedNode,
         AstNode;
 import 'package:analyzer/src/generated/engine.dart'
     show ParseDartTask, AnalysisContext;
 import 'package:analyzer/src/generated/source.dart' show Source;
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/analyzer.dart' show parseDirectives;
 import 'package:crypto/crypto.dart' show CryptoUtils, MD5;
 import 'package:source_span/source_span.dart';
+import 'package:yaml/yaml.dart';
 
 import 'js/keywords.dart';
 
 bool isDartPrivateLibrary(LibraryElement library) {
   var uri = library.source.uri;
   if (uri.scheme != "dart") return false;
   return Identifier.isPrivateName(uri.path);
 }
 
 /// Choose a canonical name from the library element. This is safe to use as a
@@ skipping 272 matching lines @@
 
   if (resourceUri.scheme != 'file') return null;
   var filepath = resourceUri.path;
   var relativePath = path.relative(filepath, from: path.dirname(entryUri.path));
 
   // File:/// urls can be for resources in the same project or resources from
   // the dev_compiler package. For now we only support relative paths going
   // further inside the folder where the entrypoint is located, otherwise we
   // assume this is a runtime resource from the dev_compiler.
   if (!relativePath.startsWith('..')) return relativePath;
-  var segments = resourceUri.pathSegments;
-  var len = segments.length;
-  if (segments.length < 4 ||
-      segments[len - 2] != 'runtime' ||
-      segments[len - 3] != 'lib' ||
-      // If loaded from sources this will be exactly dev_compiler, otherwise it
-      // can be the name in the pub cache (typically dev_compiler-version).
-      !segments[len - 4].startsWith('dev_compiler')) {
-    return null;
-  }
-  return path.joinAll(['dev_compiler']..addAll(segments.skip(len - 2)));
+
+  // Expect the code to live under lib/runtime/ in the dev_compiler's folder.
+  var filename = path.basename(filepath);
+  var dir = path.dirname(filepath);
+  if (path.basename(dir) != 'runtime') return null;
+  dir = path.dirname(dir);
+  if (path.basename(dir) != 'lib') return null;
+  dir = path.dirname(dir);
+  var pubspec =
+      loadYaml(new File(path.join(dir, 'pubspec.yaml')).readAsStringSync());
+
+  // Ensure this is loaded from the dev_compiler package.
+  if (pubspec['name'] != 'dev_compiler') return null;
+  return path.join('dev_compiler', 'runtime', filename);
 }