Object.observe: generate change records for named properties.

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index 28e4af53682b2fa6a55623914720d7939bbd0285..68b844feaf64448dfc195c6606cdee7ded71f7e7 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -161,7 +161,8 @@ enum BindingFlags {
   V(DERIVED_HAS_TRAP_INDEX, JSFunction, derived_has_trap) \
   V(DERIVED_GET_TRAP_INDEX, JSFunction, derived_get_trap) \
   V(DERIVED_SET_TRAP_INDEX, JSFunction, derived_set_trap) \
-  V(PROXY_ENUMERATE, JSFunction, proxy_enumerate) \
+  V(PROXY_ENUMERATE_INDEX, JSFunction, proxy_enumerate) \
+  V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \
   V(RANDOM_SEED_INDEX, ByteArray, random_seed)
 
 // JSFunctions are pairs (context, function code), sometimes also called
@@ -288,7 +289,8 @@ class Context: public FixedArray {
     DERIVED_HAS_TRAP_INDEX,
     DERIVED_GET_TRAP_INDEX,
     DERIVED_SET_TRAP_INDEX,
-    PROXY_ENUMERATE,
+    PROXY_ENUMERATE_INDEX,
+    OBSERVERS_NOTIFY_CHANGE_INDEX,
     RANDOM_SEED_INDEX,
 
     // Properties from here are treated as weak references by the full GC.