Rename ClosureVariable, use separate IR forms for declaration and assignment.

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

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js.cps_ir.optimizers;
 
 /**
  * [ShrinkingReducer] applies shrinking reductions to CPS terms as described
  * in 'Compiling with Continuations, Continued' by Andrew Kennedy.
  */
@@ skipping 494 matching lines @@
 
   processLetCont(LetCont node) {
     int index = 0;
     node.continuations.forEach((Continuation continuation) {
       continuation.parent = node;
       continuation.parent_index = index++;
     });
     node.body.parent = node;
   }
 
+  processLetMutable(LetMutable node) {
+    node.variable.parent = node;
+    node.value.parent = node;
+    node.body.parent = node;
+  }
+
   processInvokeStatic(InvokeStatic node) {
     node.arguments.forEach((Reference ref) => ref.parent = node);
     node.continuation.parent = node;
   }
 
   processInvokeContinuation(InvokeContinuation node) {
     node.continuation.parent = node;
     node.arguments.forEach((Reference ref) => ref.parent = node);
   }
 
@@ skipping 23 matching lines @@
     node.condition.parent = node;
     node.trueContinuation.parent = node;
     node.falseContinuation.parent = node;
   }
 
   processTypeOperator(TypeOperator node) {
     node.continuation.parent = node;
     node.receiver.parent = node;
   }
 
-  processSetClosureVariable(SetClosureVariable node) {
+  processSetMutableVariable(SetMutableVariable node) {
+    node.variable.parent = node;
     node.body.parent = node;
     node.value.parent = node;
   }
 
   processDeclareFunction(DeclareFunction node) {
+    node.variable.parent = node;
     node.definition.parent = node;
     node.body.parent = node;
   }
 
   // Definitions.
 
   processLiteralList(LiteralList node) {
     node.values.forEach((Reference ref) => ref.parent = node);
   }
 
@@ skipping 37 matching lines @@
   processSetField(SetField node) {
     node.object.parent = node;
     node.value.parent = node;
     node.body.parent = node;
   }
 
   processGetField(GetField node) {
     node.object.parent = node;
   }
 
+  processGetMutableVariable(GetMutableVariable node) {
+    node.variable.parent = node;
+  }
+
   processCreateInstance(CreateInstance node) {
     node.arguments.forEach((Reference ref) => ref.parent = node);
   }
 
   processCreateBox(CreateBox node) {
   }
 }
 
 class _ReductionKind {
   final String name;
@@ skipping 32 matching lines @@
   }
 
   String toString() => "$kind: $node";
 }
 
 /// A dummy class used solely to mark nodes as deleted once they are removed
 /// from a term.
 class _DeletedNode extends Node {
   accept(_) => null;
 }