Reduce use of getClosureInfoForMember and cleanup closure_test

pkg/compiler/lib/src/js_emitter/runtime_type_generator.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 dart2js.js_emitter.runtime_type_generator;
 
 import '../closure.dart'
-    show ClosureRepresentationInfo, ClosureFieldElement, ClosureConversionTask;
+    show
+        ClosureRepresentationInfo,
+        ClosureFieldElement,
+        ClosureConversionTask,
+        ScopeInfo;
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
 import '../common_elements.dart' show CommonElements, ElementEnvironment;
 import '../elements/elements.dart'
     show ClassElement, MethodElement, MixinApplicationElement;
 import '../elements/entities.dart';
 import '../elements/types.dart';
 import '../js/js.dart' as jsAst;
 import '../js/js.dart' show js;
 import '../js_backend/js_interop_analysis.dart';
@@ skipping 148 matching lines @@
           !_closedWorld.isSubclassOf(classElement, other)) {
         result.addIsTest(other, _namer.operatorIs(other), js('1'));
       }
     }
 
     void generateFunctionTypeSignature(
         FunctionEntity method, FunctionType type) {
       assert(!(method is MethodElement && !method.isImplementation));
       jsAst.Expression thisAccess = new jsAst.This();
       if (!method.isAbstract) {
-        ClosureRepresentationInfo closureData =
-            _closureDataLookup.getClosureInfoForMember(method);
-        if (closureData != null) {
-          ClosureFieldElement thisLocal = closureData.thisFieldEntity;
+        ScopeInfo scopeInfo = _closureDataLookup.getScopeInfo(method);
+        if (scopeInfo is ClosureRepresentationInfo) {
+          ClosureFieldElement thisLocal = scopeInfo.thisFieldEntity;
           if (thisLocal != null) {
             jsAst.Name thisName = _namer.instanceFieldPropertyName(thisLocal);
             thisAccess = js('this.#', thisName);
           }
         }
       }
 
       if (storeFunctionTypeInMetadata && !type.containsTypeVariables) {
         result.functionTypeIndex =
             emitterTask.metadataCollector.reifyType(type);
@@ skipping 198 matching lines @@
 
     // We need to also emit "is checks" for the superclass and its supertypes.
     ClassEntity superclass = _elementEnvironment.getSuperClass(cls);
     if (superclass != null) {
       tryEmitTest(superclass);
       _generateInterfacesIsTests(
           superclass, generateIsTest, generateSubstitution, alreadyGenerated);
     }
   }
 }