Make field-get/set work without elements.

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index a66dbaf7c2a4c7ff9fa48ead04383232ebeafb22..3ecbeffd22a75623dd9985e0c8d78c41969210b8 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -396,7 +396,7 @@ class LocalsHandler {
     } else if (isStoredInClosureField(element)) {
       Element redirect = redirectionMapping[element];
       HInstruction receiver = readLocal(closureData.closureElement);
-      HInstruction fieldGet = new HFieldGet(redirect, receiver);
+      HInstruction fieldGet = new HFieldGet.withElement(redirect, receiver);
       builder.add(fieldGet);
       return fieldGet;
     } else if (isBoxed(element)) {
@@ -408,7 +408,7 @@ class LocalsHandler {
       // the box.
       assert(redirect.enclosingElement.kind == ElementKind.VARIABLE);
       HInstruction box = readLocal(redirect.enclosingElement);
-      HInstruction lookup = new HFieldGet(redirect, box);
+      HInstruction lookup = new HFieldGet.withElement(redirect, box);
       builder.add(lookup);
       return lookup;
     } else {
@@ -468,7 +468,7 @@ class LocalsHandler {
       // be accessed directly.
       assert(redirect.enclosingElement.kind == ElementKind.VARIABLE);
       HInstruction box = readLocal(redirect.enclosingElement);
-      builder.add(new HFieldSet(redirect, box, value));
+      builder.add(new HFieldSet.withElement(redirect, box, value));
     } else {
       assert(isUsedInTry(element));
       HLocalValue local = getLocal(element);