Merge CommonElements and BackendHelpers!

pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart

Index: pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart b/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
index 2c8ba44958ccc2a8f73df3d31a5b310d4d0003d8..a0ce8a667ba03e5720d586fbf10a706dc5b5ab2b 100644
--- a/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
@@ -32,7 +32,6 @@ import '../../elements/elements.dart'
 import '../../elements/entities.dart';
 import '../../elements/types.dart' show DartType;
 import '../../js/js.dart' as js;
-import '../../js_backend/backend_helpers.dart' show BackendHelpers;
 import '../../js_backend/js_backend.dart'
     show Namer, JavaScriptBackend, JavaScriptConstantCompiler, StringBackedName;
 import '../../universe/selector.dart' show Selector;
@@ -86,7 +85,6 @@ class ProgramBuilder {
         this._registry = new Registry(compiler);
 
   JavaScriptBackend get backend => _compiler.backend;
-  BackendHelpers get helpers => backend.helpers;
   CodegenWorldBuilder get worldBuilder => _compiler.codegenWorldBuilder;
 
   /// Mapping from [ClassElement] to constructed [Class]. We need this to
@@ -347,7 +345,8 @@ class ProgramBuilder {
     // a regular getter that returns a JavaScript function and tearing off
     // a method in the case where there exist multiple JavaScript classes
     // that conflict on whether the member is a getter or a method.
-    var interceptorClass = _classes[helpers.jsJavaScriptObjectClass];
+    var interceptorClass =
+        _classes[_compiler.commonElements.jsJavaScriptObjectClass];
     var stubNames = new Set<String>();
     librariesMap.forEach((LibraryElement library, List<Element> elements) {
       for (Element e in elements) {
@@ -475,7 +474,7 @@ class ProgramBuilder {
         .map(_buildStaticMethod)
         .toList();
 
-    if (library == helpers.interceptorsLibrary) {
+    if (library == _compiler.commonElements.interceptorsLibrary) {
       statics.addAll(_generateGetInterceptorMethods());
       statics.addAll(_generateOneShotInterceptors());
     }
@@ -552,7 +551,7 @@ class ProgramBuilder {
       });
     }
 
-    if (element == helpers.closureClass) {
+    if (element == _compiler.commonElements.closureClass) {
       // We add a special getter here to allow for tearing off a closure from
       // itself.
       js.Name name = namer.getterForMember(Names.call);
@@ -585,7 +584,7 @@ class ProgramBuilder {
     List<StubMethod> isChecks = <StubMethod>[];
     if (backend.nativeData.isJsInteropClass(element)) {
       typeTests.properties.forEach((js.Name name, js.Node code) {
-        _classes[helpers.jsInterceptorClass]
+        _classes[_compiler.commonElements.jsInterceptorClass]
             .isChecks
             .add(_buildStubMethod(name, code));
       });
@@ -824,8 +823,8 @@ class ProgramBuilder {
     InterceptorStubGenerator stubGenerator =
         new InterceptorStubGenerator(_compiler, namer, backend, closedWorld);
 
-    String holderName =
-        namer.globalObjectForLibrary(helpers.interceptorsLibrary);
+    String holderName = namer
+        .globalObjectForLibrary(_compiler.commonElements.interceptorsLibrary);
     // TODO(floitsch): we shouldn't update the registry in the middle of
     // generating the interceptor methods.
     Holder holder = _registry.registerHolder(holderName);
@@ -892,8 +891,8 @@ class ProgramBuilder {
     InterceptorStubGenerator stubGenerator =
         new InterceptorStubGenerator(_compiler, namer, backend, closedWorld);
 
-    String holderName =
-        namer.globalObjectForLibrary(helpers.interceptorsLibrary);
+    String holderName = namer
+        .globalObjectForLibrary(_compiler.commonElements.interceptorsLibrary);
     // TODO(floitsch): we shouldn't update the registry in the middle of
     // generating the interceptor methods.
     Holder holder = _registry.registerHolder(holderName);