Move remaining helpers to BackendHelpers

pkg/compiler/lib/src/common/backend_api.dart

 // Copyright (c) 2012, 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 dart2js.backend_api;
 
 import 'dart:async' show Future;
 
 import '../common.dart';
 import '../compiler.dart' show
@@ skipping 18 matching lines @@
     LibraryElement,
     MetadataAnnotation;
 import '../enqueue.dart' show
     Enqueuer,
     CodegenEnqueuer,
     ResolutionEnqueuer;
 import '../io/code_output.dart' show
     CodeBuffer;
 import '../io/source_information.dart' show
     SourceInformationStrategy;
+import '../js_backend/backend_helpers.dart' as js_backend show
+    BackendHelpers;
 import '../js_backend/js_backend.dart' as js_backend show
     JavaScriptBackend;
 import '../library_loader.dart' show
     LibraryLoader,
     LoadedLibraries;
 import '../native/native.dart' as native show
     NativeEnqueuer,
     maybeEnableNative;
 import '../patch_parser.dart' show
     checkNativeAnnotation, checkJsInteropAnnotation;
@@ skipping 230 matching lines @@
   /// defines the implementation of [element].
   FunctionElement resolveExternalFunction(FunctionElement element) => element;
 
   /// Returns `true` if [library] is a backend specific library whose members
   /// have special treatment, such as being allowed to extends blacklisted
   /// classes or member being eagerly resolved.
   bool isBackendLibrary(LibraryElement library) {
     // TODO(johnniwinther): Remove this when patching is only done by the
     // JavaScript backend.
     Uri canonicalUri = library.canonicalUri;
-    if (canonicalUri == js_backend.JavaScriptBackend.DART_JS_HELPER ||
-        canonicalUri == js_backend.JavaScriptBackend.DART_INTERCEPTORS) {
+    if (canonicalUri == js_backend.BackendHelpers.DART_JS_HELPER ||
+        canonicalUri == js_backend.BackendHelpers.DART_INTERCEPTORS) {
       return true;
     }
     return false;
   }
 
   void registerStaticUse(Element element, Enqueuer enqueuer) {}
 
   /// This method is called immediately after the [LibraryElement] [library] has
   /// been created.
   void onLibraryCreated(LibraryElement library) {}
@@ skipping 118 matching lines @@
   /// Returns the constant expression of [node], or `null` if [node] is not
   /// a constant expression.
   ConstantExpression getConstant(Node node);
 
   /// Registers [type] as instantiated.
   void registerInstantiatedType(InterfaceType type);
 
   /// Resolves [typeName] to a type in the context of [node].
   DartType resolveTypeFromString(Node node, String typeName);
 }