Cleanup adding elements and in particular dictionary elements

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 083bce8b54aac80d26aade82102e255cf61ea6a1..6ac1374b1e8e2f585ba67443b76981279a65e176 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2015,14 +2015,11 @@ class JSObject: public JSReceiver {
   // an access at key?
   bool WouldConvertToSlowElements(uint32_t index);
   inline bool WouldConvertToSlowElements(Handle<Object> key);
-  // Do we want to keep the elements in fast case when increasing the
-  // capacity?
-  bool ShouldConvertToSlowElements(int new_capacity);
-  // Returns true if the backing storage for the slow-case elements of
-  // this object takes up nearly as much space as a fast-case backing
-  // storage would.  In that case the JSObject should have fast
-  // elements.
-  bool ShouldConvertToFastElements();
+  // Do we want to keep fast elements when adding an element at |index|?
+  // Returns |new_capacity| indicating to which capacity the object should be
+  // increased.
+  bool ShouldConvertToSlowElements(uint32_t capacity, uint32_t index,
+                                   uint32_t* new_capacity);
   ElementsKind BestFittingFastElementsKind();
 
   // Computes the new capacity when expanding the elements of a JSObject.
@@ -10140,10 +10137,6 @@ class JSArray: public JSObject {
   // is set to a smi. This matches the set function on FixedArray.
   inline void set_length(Smi* length);
 
-  static void JSArrayUpdateLengthFromIndex(Handle<JSArray> array,
-                                           uint32_t index,
-                                           Handle<Object> value);
-
   static bool HasReadOnlyLength(Handle<JSArray> array);
   static bool WouldChangeReadOnlyLength(Handle<JSArray> array, uint32_t index);
   static MaybeHandle<Object> ReadOnlyLengthError(Handle<JSArray> array);