dart2js: Measure time of individual optimization passes.

tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart

Index: tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
diff --git a/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart b/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
index ac16a08a37cc9be56be14aaa0231577c8c8c786c..5a2a9e18a832907c2b8a0303afeb7910040040de 100644
--- a/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
+++ b/tests/compiler/dart2js/js_backend_cps_ir_source_information_test.dart
@@ -78,7 +78,8 @@ runTests(List<TestEntry> tests) {
       }
 
       Uri uri = Uri.parse('memory:$TEST_MAIN_FILE');
-      compiler.irBuilder.builderCallback = cacheIrNodeForMain;
+      compiler.backend.functionCompiler.cpsBuilderTask.builderCallback =
+          cacheIrNodeForMain;
 
       return compiler.run(uri).then((bool success) {
         Expect.isTrue(success);