Retry landing "Implement zone-allocated types"

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 9c1a9cd69f5ee0ceba6416fdba0a2309660f541b..636113d439e3f21288435e1dae6df74b27bab3b1 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -7905,6 +7905,14 @@ MaybeObject* PolymorphicCodeCacheHashTable::Put(MapHandleList* maps,
 }
 
 
+void FixedArray::Shrink(int new_length) {
+  ASSERT(0 <= new_length && new_length <= length());
+  if (new_length < length()) {
+    RightTrimFixedArray<FROM_MUTATOR>(GetHeap(), this, length() - new_length);
+  }
+}
+
+
 MaybeObject* FixedArray::AddKeysFromJSArray(JSArray* array) {
   ElementsAccessor* accessor = array->GetElementsAccessor();
   MaybeObject* maybe_result =