Implement dynamic function checks.

dart/sdk/lib/_internal/compiler/implementation/js_emitter/container_builder.dart

 // Copyright (c) 2013, 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.js_emitter;
 
 /// This class should morph into something that makes it easy to build
 /// JavaScript representations of libraries, class-sides, and instance-sides.
 /// Initially, it is just a placeholder for code that is moved from
 /// [CodeEmitterTask].
@@ skipping 304 matching lines @@
         RuntimeTypes rti = backend.rti;
         // [:() => null:] is dummy encoding of [this] which is never needed for
         // the encoding of the type of the static [method].
         jsAst.Expression encoding =
             rti.getSignatureEncoding(methodType, js('null'));
         String operatorSignature = namer.operatorSignature();
         // TODO(johnniwinther): Make MiniJsParser support function expressions.
         closureBuilder.addProperty(operatorSignature, encoding);
       }
 
-      void emitIsFunctionTypeTest(FunctionType functionType) {
-        String operator = namer.operatorIsType(functionType);
-        closureBuilder.addProperty(operator, js('true'));
-      }
-
       FunctionType methodType = element.computeType(compiler);
       Map<FunctionType, bool> functionTypeChecks =
           task.typeTestEmitter.getFunctionTypeChecksOn(methodType);
       task.typeTestEmitter.generateFunctionTypeTests(
           element, methodType, functionTypeChecks,
-          emitFunctionTypeSignature, emitIsFunctionTypeTest);
+          emitFunctionTypeSignature);
 
       closureClassElement =
           addClosureIfNew(closureBuilder, closureClassElement, fieldNames);
       staticGetters[element] = closureClassElement;
 
     }
   }
 
   ClassElement addClosureIfNew(ClassBuilder builder,
                                ClassElement closure,
@@ skipping 103 matching lines @@
 
     addParameterStubs(callElement, boundClosureBuilder.addProperty);
 
     void emitFunctionTypeSignature(Element method, FunctionType methodType) {
       jsAst.Expression encoding = backend.rti.getSignatureEncoding(
           methodType, js('this')[fieldNames[0]]);
       String operatorSignature = namer.operatorSignature();
       boundClosureBuilder.addProperty(operatorSignature, encoding);
     }
 
-    void emitIsFunctionTypeTest(FunctionType functionType) {
-      String operator = namer.operatorIsType(functionType);
-      boundClosureBuilder.addProperty(operator,
-          new jsAst.LiteralBool(true));
-    }
-
     DartType memberType = member.computeType(compiler);
     Map<FunctionType, bool> functionTypeChecks =
         task.typeTestEmitter.getFunctionTypeChecksOn(memberType);
 
     task.typeTestEmitter.generateFunctionTypeTests(
         member, memberType, functionTypeChecks,
-        emitFunctionTypeSignature, emitIsFunctionTypeTest);
+        emitFunctionTypeSignature);
 
     closureClassElement =
         addClosureIfNew(boundClosureBuilder, closureClassElement, fieldNames);
 
     String closureClass = namer.isolateAccess(closureClassElement);
 
     // And finally the getter.
     String getterName = namer.getterName(member);
     String targetName = namer.instanceMethodName(member);
 
@@ skipping 147 matching lines @@
       if (!parameters.optionalParameters.isEmpty) {
         addParameterStubs(member, builder.addProperty);
       }
     }
   }
 
   void addMemberField(VariableElement member, ClassBuilder builder) {
     // For now, do nothing.
   }
 }