Bugfix for 349874: we incorrectly believe we saw a growing store

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index f90662fc6c03e84109486bc83c794ae9ddb2493a..17a60fb4e2e81a9a88cca22f5388c9e3530de461 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2412,6 +2412,9 @@ class JSObject: public JSReceiver {
       uint32_t arg_count,
       EnsureElementsMode mode);
 
+  // Would we convert a fast elements array to dictionary mode given
+  // an access at key?
+  bool WouldConvertToSlowElements(Handle<Object> key);
   // Do we want to keep the elements in fast case when increasing the
   // capacity?
   bool ShouldConvertToSlowElements(int new_capacity);