dart2js cps: Support --trust-primitives and --trust-type-annotations.

pkg/compiler/lib/src/cps_ir/cps_ir_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.
 
 library dart2js.ir_builder;
 
 import '../closure.dart' hide ClosureScope;
 import '../common.dart';
 import '../common/names.dart' show
     Names,
@@ skipping 2795 matching lines @@
 
   ir.Node buildAwait(ir.Primitive value) {
     return _continueWithExpression((k) => new ir.Await(value, k));
   }
 
   void buildYield(ir.Primitive value, bool hasStar) {
     _continueWithExpression((k) {
       return new ir.Yield(value, hasStar, k);
     });
   }
+
+  ir.Primitive buildRefinement(ir.Primitive value, TypeMask type) {
+    return addPrimitive(new ir.Refinement(value, type));
+  }
 }
 
 /// Location of a variable relative to a given closure.
 class ClosureLocation {
   /// If not `null`, this location is [box].[field].
   /// The location of [box] can be obtained separately from an
   /// enclosing [ClosureEnvironment] or [ClosureScope].
   /// If `null`, then the location is [field] on the enclosing function object.
   final BoxLocal box;
 
@@ skipping 60 matching lines @@
 }
 
 class SwitchCaseInfo {
   final List<ir.Primitive> constants = <ir.Primitive>[];
   final SubbuildFunction buildBody;
 
   SwitchCaseInfo(this.buildBody);
 
   void addConstant(ir.Primitive constant) => constants.add(constant);
 }