Get rid of ConvertFieldToDescriptor and simplify related code.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index c75a419072654a7a62e5863c0d61d7cbd768b674..7ce339f6f488c4575c79ff74954536c7032a9a7a 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2499,7 +2499,8 @@ class JSObject: public JSReceiver {
   MUST_USE_RESULT MaybeObject* AddConstantProperty(
       Name* name,
       Object* constant,
-      PropertyAttributes attributes);
+      PropertyAttributes attributes,
+      TransitionFlag flag);
 
   MUST_USE_RESULT MaybeObject* ReplaceSlowProperty(
       Name* name,
@@ -2522,14 +2523,6 @@ class JSObject: public JSReceiver {
   MUST_USE_RESULT MaybeObject* TransitionElementsKind(ElementsKind to_kind);
   MUST_USE_RESULT MaybeObject* UpdateAllocationSite(ElementsKind to_kind);
 
-  // Converts a descriptor of any other type to a real field, backed by the
-  // properties array.
-  MUST_USE_RESULT MaybeObject* ConvertDescriptorToField(
-      Name* name,
-      Object* new_value,
-      PropertyAttributes attributes,
-      TransitionFlag flag = OMIT_TRANSITION);
-
   MUST_USE_RESULT MaybeObject* MigrateToMap(Map* new_map);
   MUST_USE_RESULT MaybeObject* GeneralizeFieldRepresentation(
       int modify_index,
@@ -2542,7 +2535,8 @@ class JSObject: public JSReceiver {
       Object* value,
       PropertyAttributes attributes,
       StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED,
-      ValueType value_type = OPTIMAL_REPRESENTATION);
+      ValueType value_type = OPTIMAL_REPRESENTATION,
+      TransitionFlag flag = INSERT_TRANSITION);
 
   // Add a property to a slow-case object.
   MUST_USE_RESULT MaybeObject* AddSlowProperty(Name* name,
@@ -2558,7 +2552,8 @@ class JSObject: public JSReceiver {
       StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED,
       ExtensibilityCheck extensibility_check = PERFORM_EXTENSIBILITY_CHECK,
       ValueType value_type = OPTIMAL_REPRESENTATION,
-      StoreMode mode = ALLOW_AS_CONSTANT);
+      StoreMode mode = ALLOW_AS_CONSTANT,
+      TransitionFlag flag = INSERT_TRANSITION);
 
   // Convert the object to use the canonical dictionary
   // representation. If the object is expected to have additional properties
@@ -2694,7 +2689,8 @@ class JSObject: public JSReceiver {
   // Maximal number of fast properties for the JSObject. Used to
   // restrict the number of map transitions to avoid an explosion in
   // the number of maps for objects used as dictionaries.
-  inline bool TooManyFastProperties(int properties, StoreFromKeyed store_mode);
+  inline bool TooManyFastProperties(
+      StoreFromKeyed store_mode = MAY_BE_STORE_FROM_KEYED);
 
   // Maximal number of elements (numbered 0 .. kMaxElementCount - 1).
   // Also maximal value of JSArray's length property.