Split resolution into several libraries.

pkg/compiler/lib/src/common/codegen.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.common.codegen;
 
 import '../compiler.dart' show
     Compiler;
 import '../constants/values.dart' show
     ConstantValue;
 import '../dart_types.dart' show
     DartType,
     InterfaceType;
 import '../diagnostics/invariant.dart' show
     invariant;
 import '../elements/elements.dart' show
     AstElement,
     ClassElement,
     Element,
     FunctionElement,
     LocalFunctionElement;
 import '../enqueue.dart' show
     CodegenEnqueuer,
     WorldImpact;
 import '../js_backend/js_backend.dart' show
     JavaScriptBackend;
-import '../resolution/resolution.dart' show
+import '../resolution/tree_elements.dart' show
     TreeElements;
 import '../universe/universe.dart' show
     Selector,
     UniverseSelector;
 import '../util/util.dart' show
     Setlet;
 import 'registry.dart' show
     Registry;
 import 'work.dart' show
     ItemCompilationContext,
@@ skipping 159 matching lines @@
 
   TreeElements get resolutionTree => element.resolvedAst.elements;
 
   WorldImpact run(Compiler compiler, CodegenEnqueuer world) {
     if (world.isProcessed(element)) return const WorldImpact();
 
     registry = new CodegenRegistry(compiler, resolutionTree);
     return compiler.codegen(this, world);
   }
 }