dart2js cps: Introduce GetStatic/SetStatic.

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 127ae915abe69d7cc432a7d9674923d30468185a..5b5f16864322b713cdc886a056a105510e47bf00 100644
--- a/pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart
+++ b/pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart
@@ -662,5 +662,17 @@ class Builder implements cps_ir.Visitor<Node> {
         node.dartType,
         node.arguments.map(getVariableUse).toList());
   }
+
+  Expression visitGetStatic(cps_ir.GetStatic node) {
+    return new GetStatic(node.element, node.sourceInformation);
+  }
+
+  Statement visitSetStatic(cps_ir.SetStatic node) {
+    SetStatic setStatic = new SetStatic(
+        node.element,
+        getVariableUse(node.value),
+        node.sourceInformation);
+    return new ExpressionStatement(setStatic, visit(node.body));
+  }
 }