dart2js cps_ir: BuiltinOperation improvements.

pkg/compiler/lib/src/cps_ir/type_mask_system.dart

Index: pkg/compiler/lib/src/cps_ir/type_mask_system.dart
diff --git a/pkg/compiler/lib/src/cps_ir/type_mask_system.dart b/pkg/compiler/lib/src/cps_ir/type_mask_system.dart
index b8167b7447c522df44380ece440b2acdb3ae4d1a..c2d704291545fe865a83285849b38ed31c4afc94 100644
--- a/pkg/compiler/lib/src/cps_ir/type_mask_system.dart
+++ b/pkg/compiler/lib/src/cps_ir/type_mask_system.dart
@@ -38,6 +38,10 @@ class TypeMaskSystem {
   TypeMask get nullType => inferrer.nullType;
   TypeMask get extendableNativeListType => backend.extendableArrayType;
 
+  TypeMask get uint31Type => inferrer.uint31Type;
+  TypeMask get uint32Type => inferrer.uint32Type;
+  TypeMask get uintType => inferrer.positiveIntType;
+
   TypeMask numStringBoolType;
   TypeMask interceptorType;
 
@@ -199,6 +203,21 @@ class TypeMaskSystem {
     return t.satisfies(backend.jsIntClass, classWorld);
   }
 
+  bool isDefinitelyUint31(TypeMask t, {bool allowNull: false}) {
+    if (!allowNull && t.isNullable) return false;
+    return t.satisfies(backend.jsUInt31Class, classWorld);
+  }
+
+  bool isDefinitelyUint32(TypeMask t, {bool allowNull: false}) {
+    if (!allowNull && t.isNullable) return false;
+    return t.satisfies(backend.jsUInt32Class, classWorld);
+  }
+
+  bool isDefinitelyUint(TypeMask t, {bool allowNull: false}) {
+    if (!allowNull && t.isNullable) return false;
+    return t.satisfies(backend.jsPositiveIntClass, classWorld);
+  }
+
   // TODO(sra): Find a better name.  'NativeList' is a bad name because there
   // are many native classes in dart:html that implement List but are not (and
   // should not be) included in this predicate.