Replaced Value by Definition in the renaming environment.

runtime/vm/flow_graph.h

Index: runtime/vm/flow_graph.h
diff --git a/runtime/vm/flow_graph.h b/runtime/vm/flow_graph.h
index 8e75e07c6e573acca6b2c7fa2ce5006cd0d18bc1..e76dd22c4cb71da0bf0e9dba2d36e9b0f2c5b098 100644
--- a/runtime/vm/flow_graph.h
+++ b/runtime/vm/flow_graph.h
@@ -11,10 +11,10 @@
 namespace dart {
 
 class BlockEntryInstr;
+class Definition;
 class FlowGraphBuilder;
 class GraphEntryInstr;
 class PhiInstr;
-class Value;
 
 // Class to incapsulate the construction and manipulation of the flow graph.
 class FlowGraph: public ZoneAllocated {
@@ -80,7 +80,7 @@ class FlowGraph: public ZoneAllocated {
   void Rename(GrowableArray<PhiInstr*>* live_phis);
   void RenameRecursive(
       BlockEntryInstr* block_entry,
-      GrowableArray<Value*>* env,
+      GrowableArray<Definition*>* env,
       GrowableArray<PhiInstr*>* live_phis);
 
   void InsertPhis(