dart2js cps: Always use interceptors and type tags for 'is' checks.

pkg/compiler/lib/src/js_backend/codegen/glue.dart

Index: pkg/compiler/lib/src/js_backend/codegen/glue.dart
diff --git a/pkg/compiler/lib/src/js_backend/codegen/glue.dart b/pkg/compiler/lib/src/js_backend/codegen/glue.dart
index 277cf6e1c891c8a3c75111b1b632926eb499daf6..c44da0ea6afe199db3e24700ae45a9110af4fe4b 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/glue.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/glue.dart
@@ -199,26 +199,11 @@ class Glue {
     return representation;
   }
 
-  bool isNativePrimitiveType(DartType type) {
-    if (type is! InterfaceType) return false;
-    return _backend.isNativePrimitiveType(type.element);
-  }
-
   void registerIsCheck(DartType type, Registry registry) {
     _enqueuer.registerIsCheck(type, registry);
     _backend.registerIsCheckForCodegen(type, _enqueuer, registry);
   }
 
-  bool isIntClass(ClassElement cls) => cls == _compiler.intClass;
-
-  bool isStringClass(ClassElement cls) => cls == _compiler.stringClass;
-
-  bool isBoolClass(ClassElement cls) => cls == _compiler.boolClass;
-
-  bool isNumClass(ClassElement cls) => cls == _compiler.numClass;
-
-  bool isDoubleClass(ClassElement cls) => cls == _compiler.doubleClass;
-
   String getTypeTestTag(DartType type) {
     return _backend.namer.operatorIsType(type);
   }
@@ -226,6 +211,4 @@ class Glue {
   bool operatorEqHandlesNullArgument(FunctionElement element) {
     return _backend.operatorEqHandlesNullArgument(element);
   }
-
-  bool isListClass(ClassElement cls) => cls == _compiler.listClass;
 }