Heavy cleanup of the external pointer API.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index a368eefe766985547d2e2f8cbe37a07dff4418dd..0fac90deac82cccccfdcca698a53cb4ede1ab508 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1240,8 +1240,8 @@ bool Genesis::InitializeGlobal(Handle<GlobalObject> inner_global,
   // Initialize the out of memory slot.
   native_context()->set_out_of_memory(heap->false_value());
 
-  // Initialize the data slot.
-  native_context()->set_data(heap->undefined_value());
+  // Initialize the embedder data slot.
+  native_context()->set_embedder_data(*factory->NewFixedArray(2));
 
   {
     // Initialize the random seed slot.