Introduce BackendImpact to separate enqueueing from data.

pkg/compiler/lib/src/js_backend/codegen/glue.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library code_generator_dependencies;
 
 import '../js_backend.dart';
 import '../../common/registry.dart' show
     Registry;
 import '../../common/codegen.dart' show
@@ skipping 94 matching lines @@
     return _backend.mapLiteralConstructorEmpty;
   }
 
   FunctionElement get identicalFunction => _compiler.identicalFunction;
 
   js.Name invocationName(Selector selector) {
     return _namer.invocationName(selector);
   }
 
   FunctionElement get createInvocationMirrorMethod {
-    return _backend.getCreateInvocationMirror();
+    return _backend.helpers.createInvocationMirror;
   }
 
   void registerUseInterceptorInCodegen() {
     _backend.registerUseInterceptor(_enqueuer);
   }
 
   bool isInterceptedSelector(Selector selector) {
     return _backend.isInterceptedSelector(selector);
   }
 
@@ skipping 38 matching lines @@
   js.Name getInterceptorName(Set<ClassElement> interceptedClasses) {
     return _backend.namer.nameForGetInterceptor(interceptedClasses);
   }
 
   js.Expression getInterceptorLibrary() {
     return new js.VariableUse(
         _backend.namer.globalObjectFor(_backend.interceptorsLibrary));
   }
 
   FunctionElement getWrapExceptionHelper() {
-    return _backend.getWrapExceptionHelper();
+    return _backend.helpers.wrapExceptionHelper;
   }
 
   FunctionElement getExceptionUnwrapper() {
-    return _backend.getExceptionUnwrapper();
+    return _backend.helpers.exceptionUnwrapper;
   }
 
   FunctionElement getTraceFromException() {
-    return _backend.getTraceFromException();
+    return _backend.helpers.traceFromException;
   }
 
   FunctionElement getCreateRuntimeType() {
-    return _backend.getCreateRuntimeType();
+    return _backend.helpers.createRuntimeType;
   }
 
   FunctionElement getRuntimeTypeToString() {
-    return _backend.getRuntimeTypeToString();
+    return _backend.helpers.runtimeTypeToString;
   }
 
   FunctionElement getRuntimeTypeArgument() {
-    return _backend.getGetRuntimeTypeArgument();
+    return _backend.helpers.getRuntimeTypeArgument;
   }
 
   FunctionElement getTypeArgumentByIndex() {
-    return _backend.getGetTypeArgumentByIndex();
+    return _backend.helpers.getTypeArgumentByIndex;
   }
 
   FunctionElement getAddRuntimeTypeInformation() {
-    return _backend.getSetRuntimeTypeInfo();
+    return _backend.helpers.setRuntimeTypeInfo;
   }
 
   /// checkSubtype(value, $isT, typeArgs, $asT)
   FunctionElement getCheckSubtype() {
-    return _backend.getCheckSubtype();
+    return _backend.helpers.checkSubtype;
   }
 
   /// subtypeCast(value, $isT, typeArgs, $asT)
   FunctionElement getSubtypeCast() {
-    return _backend.getSubtypeCast();
+    return _backend.helpers.subtypeCast;
   }
 
   /// checkSubtypeOfRuntime(value, runtimeType)
   FunctionElement getCheckSubtypeOfRuntimeType() {
-    return _backend.getCheckSubtypeOfRuntimeType();
+    return _backend.helpers.checkSubtypeOfRuntimeType;
   }
 
   /// subtypeOfRuntimeTypeCast(value, runtimeType)
   FunctionElement getSubtypeOfRuntimeTypeCast() {
-    return _backend.getSubtypeOfRuntimeTypeCast();
+    return _backend.helpers.subtypeOfRuntimeTypeCast;
   }
 
   js.Expression getRuntimeTypeName(ClassElement cls) {
     return js.quoteName(_namer.runtimeTypeName(cls));
   }
 
   int getTypeVariableIndex(TypeVariableType variable) {
     return RuntimeTypes.getTypeVariableIndex(variable.element);
   }
 
@@ skipping 54 matching lines @@
   bool isBoolClass(ClassElement classElement) =>
       classElement == _backend.jsBoolClass ||
       classElement == _compiler.boolClass;
 
   // TODO(sra): Should this be part of CodegenRegistry?
   void registerNativeBehavior(NativeBehavior nativeBehavior, node) {
     if (nativeBehavior == null) return;
     _enqueuer.nativeEnqueuer.registerNativeBehavior(nativeBehavior, node);
   }
 }