Ensure we're looking at the correct resolved AST when initializing fields in constructors.

pkg/compiler/lib/src/ssa/graph_builder.dart

Index: pkg/compiler/lib/src/ssa/graph_builder.dart
diff --git a/pkg/compiler/lib/src/ssa/graph_builder.dart b/pkg/compiler/lib/src/ssa/graph_builder.dart
index f266b55e3a08da71de6f73dc780265222dded010..211468f85a9244dc230520cbd4539633257a0f80 100644
--- a/pkg/compiler/lib/src/ssa/graph_builder.dart
+++ b/pkg/compiler/lib/src/ssa/graph_builder.dart
@@ -11,7 +11,6 @@ import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
 import '../io/source_information.dart';
 import '../js_backend/js_backend.dart';
-import '../resolution/tree_elements.dart';
 import '../tree/tree.dart' as ast;
 import '../types/types.dart';
 import '../universe/call_structure.dart' show CallStructure;
@@ -38,9 +37,6 @@ abstract class GraphBuilder {
   /// The JavaScript backend we are targeting in this compilation.
   JavaScriptBackend get backend;
 
-  /// The tree elements for the element being built into an SSA graph.
-  TreeElements get elements;
-
   CodegenRegistry get registry;
 
   ClosedWorld get closedWorld;