Move Compiler.libraries to LibraryLoader.

tests/compiler/dart2js/deferred_follow_implicit_super_regression_test.dart

Index: tests/compiler/dart2js/deferred_follow_implicit_super_regression_test.dart
diff --git a/tests/compiler/dart2js/deferred_follow_implicit_super_regression_test.dart b/tests/compiler/dart2js/deferred_follow_implicit_super_regression_test.dart
index 8ac7838748cccb04fabfd713bdae49404ac322fe..06e9af512735ad6d285bc3e08b762f51fff736bf 100644
--- a/tests/compiler/dart2js/deferred_follow_implicit_super_regression_test.dart
+++ b/tests/compiler/dart2js/deferred_follow_implicit_super_regression_test.dart
@@ -20,13 +20,17 @@ runTest(String mainScript, test) {
 
 void main() {
   runTest('memory:main.dart', (compiler) {
+    lookupLibrary(name) {
+      return compiler.libraryLoader.lookupLibrary(Uri.parse(name));
+    }
+
     var main = compiler.mainApp.find(dart2js.Compiler.MAIN);
     Expect.isNotNull(main, "Could not find 'main'");
     compiler.deferredLoadTask.onResolutionComplete(main);
 
     var outputUnitForElement = compiler.deferredLoadTask.outputUnitForElement;
 
-    var lib = compiler.libraries["memory:lib.dart"];
+    var lib = lookupLibrary("memory:lib.dart");
     var a = lib.find("a");
     var b = lib.find("b");
     var c = lib.find("c");