Move SetFastDoubleElementsCapacity into GrowCapacityAndConvert

src/elements.h

Index: src/elements.h
diff --git a/src/elements.h b/src/elements.h
index 28b23e375e4a059c453ab82a6da33ff3f5a840cf..ad2aa40bd045eb64d3955405455029807658042a 100644
--- a/src/elements.h
+++ b/src/elements.h
@@ -121,6 +121,9 @@ class ElementsAccessor {
       *from_holder, 0, from_kind, to, 0, kCopyToEndAndInitializeToHole);
   }
 
+  virtual void GrowCapacityAndConvert(Handle<JSObject> object,
+                                      uint32_t capacity) = 0;
+
   virtual Handle<FixedArray> AddElementsToFixedArray(
       Handle<JSObject> receiver, Handle<FixedArray> to,
       FixedArray::KeyFilter filter) = 0;