Add support for fields to the new dart backend.

pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart

Index: pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
diff --git a/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart b/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
index f7f4bc11f85c3efc266f176252819e12c26571e0..46b64375a718b5d976f74e66cc012164ad02b423 100644
--- a/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
+++ b/pkg/compiler/lib/src/cps_ir/shrinking_reductions.dart
@@ -8,16 +8,13 @@ part of dart2js.optimizers;
  * [[ShrinkingReducer]] applies shrinking reductions to CPS terms as described
  * in 'Compiling with Continuations, Continued' by Andrew Kennedy.
  */
-class ShrinkingReducer implements Pass {
+class ShrinkingReducer extends Pass {
   _RedexVisitor _redexVisitor;
   Set<_ReductionTask> _worklist;
 
   static final _DeletedNode _DELETED = new _DeletedNode();
 
-  /// Applies shrinking reductions to root, mutating root in the process.
-  void rewrite(FunctionDefinition root) {
-    if (root.isAbstract) return;
-
+  void rewriteExecutableDefinition(ExecutableDefinition root) {
     _worklist = new Set<_ReductionTask>();
     _redexVisitor = new _RedexVisitor(_worklist);
 
@@ -25,7 +22,7 @@ class ShrinkingReducer implements Pass {
     new ParentVisitor().visit(root);
 
     // Sweep over the term, collecting redexes into the worklist.
-    _redexVisitor.visitFunctionDefinition(root);
+    _redexVisitor.visit(root);
 
     // Process the worklist.
     while (_worklist.isNotEmpty) {
@@ -35,6 +32,17 @@ class ShrinkingReducer implements Pass {
     }
   }
 
+  /// Applies shrinking reductions to root, mutating root in the process.
+  void rewriteFieldDefinition(FieldDefinition root) {
+    rewriteExecutableDefinition(root);
+  }
+
+  /// Applies shrinking reductions to root, mutating root in the process.
+  void rewriteFunctionDefinition(FunctionDefinition root) {
+    if (root.isAbstract) return;
+    rewriteExecutableDefinition(root);
+  }
+
   /// Removes the given node from the CPS graph, replacing it with its body
   /// and marking it as deleted. The node's parent must be a [[InteriorNode]].
   void _removeNode(InteriorNode node) {
@@ -295,6 +303,10 @@ class _RemovalRedexVisitor extends _RedexVisitor {
 /// Traverses the CPS term and sets node.parent for each visited node.
 class ParentVisitor extends RecursiveVisitor {
 
+  processFieldDefinition(FieldDefinition node) {
+    node.body.parent = node;
+  }
+
   processFunctionDefinition(FunctionDefinition node) {
     node.body.parent = node;
     node.parameters.forEach((Parameter p) => p.parent = node);