Extract CallStructure from Selector.

pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart

Index: pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
diff --git a/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart b/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
index 6b4b60e06ab53dae05e9ead2170935c214a39c8a..a5a07eff60165899671ce8ee73ffad5f2f713ce9 100644
--- a/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
+++ b/pkg/compiler/lib/src/dart_backend/backend_ast_emitter.dart
@@ -1161,12 +1161,12 @@ class ConstantEmitter
   @override
   Expression visitConstructed(ConstructedConstantExpression exp,
                               BuilderContext<Statement> context) {
-    int positionalArgumentCount = exp.selector.positionalArgumentCount;
+    int positionalArgumentCount = exp.callStructure.positionalArgumentCount;
     List<Argument> args = new List<Argument>.generate(
         positionalArgumentCount,
         (i) => visit(exp.arguments[i], context));
-    for (int i = 0; i < exp.selector.namedArgumentCount; ++i) {
-      args.add(new NamedArgument(exp.selector.namedArguments[i],
+    for (int i = 0; i < exp.callStructure.namedArgumentCount; ++i) {
+      args.add(new NamedArgument(exp.callStructure.namedArguments[i],
           visit(exp.arguments[positionalArgumentCount + i], context)));
     }