Refactor HInferRepresentation into an HPhase and use the phase zone.

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 97c9a6a21b1ffe9a0fefc8428c9ea1954515294f..61ac39f4a434ed6a117cd9d012459d98fb685334 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -703,25 +703,6 @@ class HEnvironment: public ZoneObject {
 };
 
 
-class HInferRepresentation BASE_EMBEDDED {
- public:
-  explicit HInferRepresentation(HGraph* graph)
-      : graph_(graph),
-        worklist_(8, graph->zone()),
-        in_worklist_(graph->GetMaximumValueID(), graph->zone()) { }
-
-  void Analyze();
-  void AddToWorklist(HValue* current);
-
- private:
-  Zone* zone() const { return graph_->zone(); }
-
-  HGraph* graph_;
-  ZoneList<HValue*> worklist_;
-  BitVector in_worklist_;
-};
-
-
 class HOptimizedGraphBuilder;
 
 enum ArgumentsAllowedFlag {