Element model cleanup + prepare for easier reimplementation.

pkg/compiler/lib/src/world.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.
 
 part of dart2js;
 
 abstract class ClassWorld {
   // TODO(johnniwinther): Refine this into a `BackendClasses` interface.
   Backend get backend;
 
@@ skipping 323 matching lines @@
 
   bool get isClosed => compiler.phase > Compiler.PHASE_RESOLVING;
 
   // Used by selectors.
   bool isAssertMethod(Element element) {
     return compiler.backend.isAssertMethod(element);
   }
 
   // Used by selectors.
   bool isForeign(Element element) {
-    return element.isForeign(compiler.backend);
+    return compiler.backend.isForeign(element);
   }
 
   Set<ClassElement> typesImplementedBySubclassesOf(ClassElement cls) {
     return _typesImplementedBySubclasses[cls.declaration];
   }
 
   World(Compiler compiler)
       : allFunctions = new FunctionSet(compiler),
         this.compiler = compiler,
         alreadyPopulated = compiler.cacheStrategy.newSet();
@@ skipping 169 matching lines @@
     // function expressions's element.
     // TODO(herhut): Generate classes for function expressions earlier.
     if (element is closureMapping.SynthesizedCallMethodElementX) {
       return getMightBePassedToApply(element.expression);
     }
     return functionsThatMightBePassedToApply.contains(element);
   }
 
   bool get hasClosedWorldAssumption => !compiler.hasIncrementalSupport;
 }