Merge CommonElements and BackendHelpers!

pkg/compiler/lib/src/ssa/graph_builder.dart

 // Copyright (c) 2016, 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.
 
 import '../closure.dart';
 import '../constants/constant_system.dart';
 import '../common/codegen.dart' show CodegenRegistry;
 import '../common_elements.dart';
 import '../compiler.dart';
 import '../diagnostics/diagnostic_listener.dart';
 import '../elements/elements.dart';
 import '../elements/entities.dart' show Entity, Local;
 import '../elements/resolution_types.dart';
-import '../js_backend/backend_helpers.dart';
 import '../js_backend/backend_usage.dart';
 import '../js_backend/constant_handler_javascript.dart';
 import '../js_backend/js_backend.dart';
 import '../js_backend/native_data.dart';
 import '../js_backend/js_interop_analysis.dart';
 import '../js_backend/interceptor_data.dart';
 import '../js_backend/mirrors_data.dart';
 import '../js_emitter/code_emitter_task.dart';
 import '../options.dart';
 import '../resolution/tree_elements.dart';
@@ skipping 53 matching lines @@
   BackendUsage get backendUsage => backend.backendUsage;
 
   Namer get namer => backend.namer;
 
   RuntimeTypesNeed get rtiNeed => backend.rtiNeed;
 
   JavaScriptConstantCompiler get constants => backend.constants;
 
   ConstantSystem get constantSystem => constants.constantSystem;
 
-  BackendHelpers get helpers => backend.helpers;
-
   RuntimeTypesEncoder get rtiEncoder => backend.rtiEncoder;
 
   FunctionInlineCache get inlineCache => backend.inlineCache;
 
   MirrorsData get mirrorsData => backend.mirrorsData;
 
   JsInteropAnalysis get jsInteropAnalysis => backend.jsInteropAnalysis;
 
   /// Used to track the locals while building the graph.
   LocalsHandler localsHandler;
@@ skipping 173 matching lines @@
     open(newBlock);
   }
 
   HInstruction callSetRuntimeTypeInfo(
       HInstruction typeInfo, HInstruction newObject);
 
   /// The element for which this SSA builder is being used.
   Element get targetElement;
   TypeBuilder get typeBuilder;
 }