dart2js cps: Type casts and related changes to type propagation.

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 4cdc447abb27603a2590edd995bed678c6cef526..4b850bd7dcb6dd218560a348e4b4db5b36b8f0e4 100644
--- a/pkg/compiler/lib/src/js_backend/codegen/glue.dart
+++ b/pkg/compiler/lib/src/js_backend/codegen/glue.dart
@@ -176,11 +176,21 @@ class Glue {
     return _backend.getCheckSubtype();
   }
 
+  /// subtypeCast(value, $isT, typeArgs, $asT)
+  FunctionElement getSubtypeCast() {
+    return _backend.getSubtypeCast();
+  }
+
   /// checkSubtypeOfRuntime(value, runtimeType)
-  FunctionElement getCheckSubtypeOfRuntime() {
+  FunctionElement getCheckSubtypeOfRuntimeType() {
     return _backend.getCheckSubtypeOfRuntimeType();
   }
 
+  /// subtypeOfRuntimeTypeCast(value, runtimeType)
+  FunctionElement getSubtypeOfRuntimeTypeCast() {
+    return _backend.getSubtypeOfRuntimeTypeCast();
+  }
+
   js.Expression getRuntimeTypeName(ClassElement cls) {
     return js.string(_namer.runtimeTypeName(cls));
   }