Delivery logic for Object.observe

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index 91de672c96c80c6a16a3ef13ce5ac83d21dc055d..7a3ab49dda471cae9ab14df6dc51b85e93433b0b 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -163,6 +163,7 @@ enum BindingFlags {
   V(DERIVED_SET_TRAP_INDEX, JSFunction, derived_set_trap) \
   V(PROXY_ENUMERATE_INDEX, JSFunction, proxy_enumerate) \
   V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \
+  V(OBSERVERS_DELIVER_CHANGES_INDEX, JSFunction, observers_deliver_changes) \
   V(RANDOM_SEED_INDEX, ByteArray, random_seed)
 
 // JSFunctions are pairs (context, function code), sometimes also called
@@ -291,6 +292,7 @@ class Context: public FixedArray {
     DERIVED_SET_TRAP_INDEX,
     PROXY_ENUMERATE_INDEX,
     OBSERVERS_NOTIFY_CHANGE_INDEX,
+    OBSERVERS_DELIVER_CHANGES_INDEX,
     RANDOM_SEED_INDEX,
 
     // Properties from here are treated as weak references by the full GC.