dart2js cps: Direct access on JS arrays.

pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart

Index: pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart
diff --git a/pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart b/pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart
index 6ca4430ebf569a99918714077052503e282eda30..c3cf4f0294d37ad67ab51f3fe30bcc27c1ab5cfb 100644
--- a/pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart
+++ b/pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart
@@ -612,5 +612,20 @@ class Builder implements cps_ir.Visitor<Node> {
           node.dependency);
     }
   }
+
+  Expression visitGetLength(cps_ir.GetLength node) {
+    return new GetLength(getVariableUse(node.object));
+  }
+
+  Expression visitGetIndex(cps_ir.GetIndex node) {
+    return new GetIndex(getVariableUse(node.object),
+                        getVariableUse(node.index));
+  }
+
+  Expression visitSetIndex(cps_ir.SetIndex node) {
+    return new SetIndex(getVariableUse(node.object),
+                        getVariableUse(node.index),
+                        getVariableUse(node.value));
+  }
 }