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

src/contexts.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 134 matching lines @@
   V(NORMALIZED_MAP_CACHE_INDEX, NormalizedMapCache, normalized_map_cache) \
   V(RUNTIME_CONTEXT_INDEX, Context, runtime_context) \
   V(CALL_AS_FUNCTION_DELEGATE_INDEX, JSFunction, call_as_function_delegate) \
   V(CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, JSFunction, \
     call_as_constructor_delegate) \
   V(SCRIPT_FUNCTION_INDEX, JSFunction, script_function) \
   V(OPAQUE_REFERENCE_FUNCTION_INDEX, JSFunction, opaque_reference_function) \
   V(CONTEXT_EXTENSION_FUNCTION_INDEX, JSFunction, context_extension_function) \
   V(OUT_OF_MEMORY_INDEX, Object, out_of_memory) \
   V(MAP_CACHE_INDEX, Object, map_cache) \
-  V(CONTEXT_DATA_INDEX, Object, data) \
+  V(EMBEDDER_DATA_INDEX, FixedArray, embedder_data) \
   V(ALLOW_CODE_GEN_FROM_STRINGS_INDEX, Object, allow_code_gen_from_strings) \
   V(ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, Object, \
     error_message_for_code_gen_from_strings) \
   V(TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, JSFunction, \
     to_complete_property_descriptor) \
   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_INDEX, JSFunction, proxy_enumerate) \
   V(OBSERVERS_NOTIFY_CHANGE_INDEX, JSFunction, observers_notify_change) \
@@ skipping 110 matching lines @@
     FUNCTION_CACHE_INDEX,
     JSFUNCTION_RESULT_CACHES_INDEX,
     NORMALIZED_MAP_CACHE_INDEX,
     RUNTIME_CONTEXT_INDEX,
     CALL_AS_FUNCTION_DELEGATE_INDEX,
     CALL_AS_CONSTRUCTOR_DELEGATE_INDEX,
     SCRIPT_FUNCTION_INDEX,
     OPAQUE_REFERENCE_FUNCTION_INDEX,
     CONTEXT_EXTENSION_FUNCTION_INDEX,
     OUT_OF_MEMORY_INDEX,
-    CONTEXT_DATA_INDEX,
+    EMBEDDER_DATA_INDEX,
     ALLOW_CODE_GEN_FROM_STRINGS_INDEX,
     ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX,
     TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX,
     DERIVED_HAS_TRAP_INDEX,
     DERIVED_GET_TRAP_INDEX,
     DERIVED_SET_TRAP_INDEX,
     PROXY_ENUMERATE_INDEX,
     OBSERVERS_NOTIFY_CHANGE_INDEX,
     OBSERVERS_DELIVER_CHANGES_INDEX,
     RANDOM_SEED_INDEX,
@@ skipping 146 matching lines @@
 
  private:
   // Unchecked access to the slots.
   Object* unchecked_previous() { return get(PREVIOUS_INDEX); }
 
 #ifdef DEBUG
   // Bootstrapping-aware type checks.
   static bool IsBootstrappingOrValidParentContext(Object* object, Context* kid);
   static bool IsBootstrappingOrGlobalObject(Object* object);
 #endif
+
+  STATIC_CHECK(kHeaderSize == Internals::kContextHeaderSize);
+  STATIC_CHECK(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONTEXTS_H_