Allocation site support for monomorphic StringAdds in BinaryOps.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 1717a5f4b59a8cba4db473b0e0634e9c9c437b93..ff85391ec562ce225b6f23785168bf24827d0daa 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -1359,7 +1359,9 @@ AllocationSiteMode AllocationSite::GetMode(ElementsKind from,
 
 inline bool AllocationSite::CanTrack(InstanceType type) {
   if (FLAG_allocation_site_pretenuring) {
-    return type == JS_ARRAY_TYPE || type == JS_OBJECT_TYPE;
+    return type == JS_ARRAY_TYPE ||
+        type == JS_OBJECT_TYPE ||
+        type < FIRST_NONSTRING_TYPE;
   }
   return type == JS_ARRAY_TYPE;
 }