Re-land rev. 12849 and 12868 (Heavy cleanup of the external pointer API + related fix).

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 0466e3113dc51e357e653783834e9c82b6df4c41..22c75a1aeb50c6abe00cab33c9b2b89c2febaaef 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1240,8 +1240,9 @@ 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.
+  Handle<FixedArray> embedder_data = factory->NewFixedArray(2);
+  native_context()->set_embedder_data(*embedder_data);
 
   {
     // Initialize the random seed slot.