Overhaul tree IR visitor and rename IR classes.

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 29a42adb91721ee62aa92f5ce52b30d2ae00310c..9ea920102e7e3325ecc4c135f1e0f732ec398dc7 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
@@ -40,18 +40,15 @@ js.Node getCodeForMain(Compiler compiler) {
   return compiler.enqueuer.codegen.generatedCode[mainFunction];
 }
 
-js.Node getJsNodeForElement(Compiler compiler,
-                                Element element) {
+js.Node getJsNodeForElement(Compiler compiler, Element element) {
   return compiler.enqueuer.codegen.generatedCode[element];
 }
 
-ir.ExecutableDefinition getIrNodeForElement(Compiler compiler,
-                                            Element element) {
+ir.RootNode getIrNodeForElement(Compiler compiler, Element element) {
   return compiler.irBuilder.getIr(element);
 }
 
-String getCodeForMethod(Compiler compiler,
-                        String name) {
+String getCodeForMethod(Compiler compiler, String name) {
   Element foundElement;
   for (Element element in compiler.enqueuer.codegen.generatedCode.keys) {
     if (element.toString() == name) {