diff --git a/src/factory.h b/src/factory.h
index 0f028e5..e68cc7e 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -54,7 +54,11 @@
       int size,
       PretenureFlag pretenure = NOT_TENURED);
 
-  Handle<NumberDictionary> NewNumberDictionary(int at_least_space_for);
+  Handle<SeededNumberDictionary> NewSeededNumberDictionary(
+      int at_least_space_for);
+
+  Handle<UnseededNumberDictionary> NewUnseededNumberDictionary(
+      int at_least_space_for);
 
   Handle<StringDictionary> NewStringDictionary(int at_least_space_for);
 
@@ -69,6 +73,8 @@
   Handle<DeoptimizationOutputData> NewDeoptimizationOutputData(
       int deopt_entry_count,
       PretenureFlag pretenure);
+  // Allocates a pre-tenured empty AccessorPair.
+  Handle<AccessorPair> NewAccessorPair();
 
   Handle<String> LookupSymbol(Vector<const char> str);
   Handle<String> LookupSymbol(Handle<String> str);
@@ -227,7 +233,7 @@
   Handle<FixedDoubleArray> CopyFixedDoubleArray(
       Handle<FixedDoubleArray> array);
 
-  // Numbers (eg, literals) are pretenured by the parser.
+  // Numbers (e.g. literals) are pretenured by the parser.
   Handle<Object> NewNumber(double value,
                            PretenureFlag pretenure = NOT_TENURED);
 
@@ -259,12 +265,19 @@
                              PretenureFlag pretenure = NOT_TENURED);
 
   Handle<JSArray> NewJSArrayWithElements(
-      Handle<FixedArray> elements,
+      Handle<FixedArrayBase> elements,
       PretenureFlag pretenure = NOT_TENURED);
 
-  void SetContent(Handle<JSArray> array, Handle<FixedArray> elements);
+  void SetElementsCapacityAndLength(Handle<JSArray> array,
+                                    int capacity,
+                                    int length);
 
-  void EnsureCanContainNonSmiElements(Handle<JSArray> array);
+  void SetContent(Handle<JSArray> array, Handle<FixedArrayBase> elements);
+
+  void EnsureCanContainHeapObjectElements(Handle<JSArray> array);
+  void EnsureCanContainElements(Handle<JSArray> array,
+                                Handle<FixedArrayBase> elements,
+                                EnsureElementsMode mode);
 
   Handle<JSProxy> NewJSProxy(Handle<Object> handler, Handle<Object> prototype);
 
@@ -423,8 +436,13 @@
       Handle<Object> stack_trace,
       Handle<Object> stack_frames);
 
-  Handle<NumberDictionary> DictionaryAtNumberPut(
-      Handle<NumberDictionary>,
+  Handle<SeededNumberDictionary> DictionaryAtNumberPut(
+      Handle<SeededNumberDictionary>,
+      uint32_t key,
+      Handle<Object> value);
+
+  Handle<UnseededNumberDictionary> DictionaryAtNumberPut(
+      Handle<UnseededNumberDictionary>,
       uint32_t key,
       Handle<Object> value);