dart2js cps: Backward redundant null check removal

pkg/compiler/lib/src/common/names.dart

Index: pkg/compiler/lib/src/common/names.dart
diff --git a/pkg/compiler/lib/src/common/names.dart b/pkg/compiler/lib/src/common/names.dart
index 27b844ff473d171386a2cce7ecb88a860a41fefd..f777c0a9f6a0496d00a03c5a2ea625a61fdbd1f7 100644
--- a/pkg/compiler/lib/src/common/names.dart
+++ b/pkg/compiler/lib/src/common/names.dart
@@ -72,6 +72,8 @@ class Names {
   static const Name CALL_NAME = Names.call;
 
   static const Name length = const PublicName(Identifiers.length);
+
+  static const Name runtimeType_ = const PublicName(Identifiers.runtimeType_);
 }
 
 /// [Selector]s commonly used.
@@ -114,13 +116,15 @@ class Selectors {
 
   static final Selector index = new Selector.index();
 
+  static final Selector runtimeType_ = new Selector.getter(Names.runtimeType_);
+
   /// List of all the selectors held in static fields.
   ///
   /// These objects are shared between different runs in batch-mode and must
   /// thus remain in the [Selector.canonicalizedValues] map.
   static final List<Selector> ALL = <Selector>[
       cancel, current, iterator, moveNext, noSuchMethod_, toString_,
-      hashCode_, compareTo, equals, length, codeUnitAt, index];
+      hashCode_, compareTo, equals, length, codeUnitAt, index, runtimeType_];
 }
 
 /// [Uri]s commonly used.