Introduce TypeFeedbackVector, as FixedArray grew constrictive.

src/type-info.h

Index: src/type-info.h
diff --git a/src/type-info.h b/src/type-info.h
index 44fecf634c4697803ccc3f418b8232e8d582221f..434ddd675983b6457aa325b0bb3d2f9e2ae41560 100644
--- a/src/type-info.h
+++ b/src/type-info.h
@@ -20,9 +20,8 @@ class SmallMapList;
 class TypeFeedbackOracle: public ZoneObject {
  public:
   TypeFeedbackOracle(Handle<Code> code,
-                     Handle<FixedArray> feedback_vector,
-                     Handle<Context> native_context,
-                     Zone* zone);
+                     Handle<TypeFeedbackVector> feedback_vector,
+                     Handle<Context> native_context, Zone* zone);
 
   bool LoadIsUninitialized(TypeFeedbackId id);
   bool StoreIsUninitialized(TypeFeedbackId id);
@@ -120,7 +119,7 @@ class TypeFeedbackOracle: public ZoneObject {
   Handle<Context> native_context_;
   Zone* zone_;
   Handle<UnseededNumberDictionary> dictionary_;
-  Handle<FixedArray> feedback_vector_;
+  Handle<TypeFeedbackVector> feedback_vector_;
 
   DISALLOW_COPY_AND_ASSIGN(TypeFeedbackOracle);
 };