Basic array capacity feedback via allocation sites.

src/elements.cc

Index: src/elements.cc
diff --git a/src/elements.cc b/src/elements.cc
index abb046725c8a0923e2ccd45aaf9826ebb9eb0453..5f768841bdefb2a903f6adcab80e487855455251 100644
--- a/src/elements.cc
+++ b/src/elements.cc
@@ -1843,7 +1843,7 @@ MaybeHandle<Object> ArrayConstructInitializeElements(Handle<JSArray> array,
         }
         return array;
       } else if (len == 0) {
-        JSArray::Initialize(array, JSArray::kPreallocatedArrayElements);
+        JSArray::Initialize(array, JSArray::PreallocatedArrayElements());
         return array;
       }
     }
@@ -1856,7 +1856,7 @@ MaybeHandle<Object> ArrayConstructInitializeElements(Handle<JSArray> array,
 
   // Optimize the case where there are no parameters passed.
   if (args->length() == 0) {
-    JSArray::Initialize(array, JSArray::kPreallocatedArrayElements);
+    JSArray::Initialize(array, JSArray::PreallocatedArrayElements());
     return array;
   }