[api] Cleaning up: Replace NeanderArray with FixedArray implementation

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index f7a2ae2fbc0109888a07974b62e0830ab6d38be7..04d583478e73da7848df183b160df21f0d2851c6 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -204,7 +204,7 @@ using v8::MemoryPressureLevel;
   V(Object, noscript_shared_function_infos, NoScriptSharedFunctionInfos)       \
   V(FixedArray, serialized_templates, SerializedTemplates)                     \
   /* Configured values */                                                      \
-  V(JSObject, message_listeners, MessageListeners)                             \
+  V(TemplateList, message_listeners, MessageListeners)                         \
   V(Code, js_entry_code, JsEntryCode)                                          \
   V(Code, js_construct_entry_code, JsConstructEntryCode)                       \
   /* Oddball maps */                                                           \
@@ -1034,6 +1034,10 @@ class Heap {
     roots_[kNoScriptSharedFunctionInfosRootIndex] = value;
   }
 
+  void SetMessageListeners(TemplateList* value) {
+    roots_[kMessageListenersRootIndex] = value;
+  }
+
   // Set the stack limit in the roots_ array.  Some architectures generate
   // code that looks here, because it is faster than loading from the static
   // jslimit_/real_jslimit_ variable in the StackGuard.