Use precompiled dependencies in pub.

sdk/lib/_internal/pub_generated/lib/src/barback/dart2js_transformer.dart

Index: sdk/lib/_internal/pub_generated/lib/src/barback/dart2js_transformer.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/barback/dart2js_transformer.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/dart2js_transformer.dart
index 50efc6527ab8fe5b59d9a90f2767f9e17b9c4d0a..6a7039f15f386f1835914cda4914fa9eb43c1598 100644
--- a/sdk/lib/_internal/pub_generated/lib/src/barback/dart2js_transformer.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/barback/dart2js_transformer.dart
@@ -87,8 +87,7 @@ class Dart2JSTransformer extends Transformer implements LazyTransformer {
         transform,
         generateSourceMaps: _generateSourceMaps);
     var id = transform.primaryInput.id;
-    var entrypoint =
-        path.join(_environment.graph.packages[id.package].dir, id.path);
+    var entrypoint = _environment.graph.packages[id.package].path(id.path);
     return Chain.track(
         dart.compile(
             entrypoint,
@@ -101,7 +100,7 @@ class Dart2JSTransformer extends Transformer implements LazyTransformer {
                 defaultsTo: _settings.mode == BarbackMode.RELEASE),
             verbose: _configBool('verbose'),
             environment: _configEnvironment,
-            packageRoot: path.join(_environment.rootPackage.dir, "packages"),
+            packageRoot: _environment.rootPackage.path("packages"),
             analyzeAll: _configBool('analyzeAll'),
             suppressWarnings: _configBool('suppressWarnings'),
             suppressHints: _configBool('suppressHints'),
@@ -167,7 +166,7 @@ class _BarbackCompilerProvider implements dart.CompilerProvider {
     var buildDir =
         _environment.getSourceDirectoryContaining(_transform.primaryInput.id.path);
     _libraryRootPath =
-        path.join(_environment.rootPackage.dir, buildDir, "packages", r"$sdk");
+        _environment.rootPackage.path(buildDir, "packages", r"$sdk");
   }
   Future<String> provideInput(Uri resourceUri) {
     assert(resourceUri.isAbsolute);
@@ -256,8 +255,8 @@ class _BarbackCompilerProvider implements dart.CompilerProvider {
     if (id != null) return id;
     var sourcePath = path.fromUri(url);
     if (_environment.containsPath(sourcePath)) {
-      var relative = path.toUri(
-          path.relative(sourcePath, from: _environment.rootPackage.dir)).toString();
+      var relative =
+          path.toUri(_environment.rootPackage.relative(sourcePath)).toString();
       return new AssetId(_environment.rootPackage.name, relative);
     }
     return null;