[snapshot] serialize embedder-provided external references.

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 1e805c0e5ddd26336e38852d0b2b158548747b39..61a2bf0cdc18356b09b5f392adbeefb69d18b4dc 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -396,35 +396,34 @@ class ThreadLocalTop BASE_EMBEDDED {
 
 typedef List<HeapObject*> DebugObjectCache;
 
-#define ISOLATE_INIT_LIST(V)                                                   \
-  /* Assembler state. */                                                       \
-  V(FatalErrorCallback, exception_behavior, NULL)                              \
-  V(LogEventCallback, event_logger, NULL)                                      \
-  V(AllowCodeGenerationFromStringsCallback, allow_code_gen_callback, NULL)     \
-  /* To distinguish the function templates, so that we can find them in the */ \
-  /* function cache of the native context. */                                  \
-  V(int, next_serial_number, 0)                                                \
-  V(ExternalReferenceRedirectorPointer*, external_reference_redirector, NULL)  \
-  /* State for Relocatable. */                                                 \
-  V(Relocatable*, relocatable_top, NULL)                                       \
-  V(DebugObjectCache*, string_stream_debug_object_cache, NULL)                 \
-  V(Object*, string_stream_current_security_token, NULL)                       \
-  V(ExternalReferenceTable*, external_reference_table, NULL)                   \
-  V(base::HashMap*, external_reference_map, NULL)                              \
-  V(base::HashMap*, root_index_map, NULL)                                      \
-  V(int, pending_microtask_count, 0)                                           \
-  V(HStatistics*, hstatistics, NULL)                                           \
-  V(CompilationStatistics*, turbo_statistics, NULL)                            \
-  V(HTracer*, htracer, NULL)                                                   \
-  V(CodeTracer*, code_tracer, NULL)                                            \
-  V(bool, fp_stubs_generated, false)                                           \
-  V(uint32_t, per_isolate_assert_data, 0xFFFFFFFFu)                            \
-  V(PromiseRejectCallback, promise_reject_callback, NULL)                      \
-  V(const v8::StartupData*, snapshot_blob, NULL)                               \
-  V(int, code_and_metadata_size, 0)                                            \
-  V(int, bytecode_and_metadata_size, 0)                                        \
-  /* true if being profiled. Causes collection of extra compile info. */       \
-  V(bool, is_profiling, false)                                                 \
+#define ISOLATE_INIT_LIST(V)                                                  \
+  /* Assembler state. */                                                      \
+  V(FatalErrorCallback, exception_behavior, nullptr)                          \
+  V(LogEventCallback, event_logger, nullptr)                                  \
+  V(AllowCodeGenerationFromStringsCallback, allow_code_gen_callback, nullptr) \
+  V(ExternalReferenceRedirectorPointer*, external_reference_redirector,       \
+    nullptr)                                                                  \
+  /* State for Relocatable. */                                                \
+  V(Relocatable*, relocatable_top, nullptr)                                   \
+  V(DebugObjectCache*, string_stream_debug_object_cache, nullptr)             \
+  V(Object*, string_stream_current_security_token, nullptr)                   \
+  V(ExternalReferenceTable*, external_reference_table, nullptr)               \
+  V(intptr_t*, api_external_references, nullptr)                              \
+  V(base::HashMap*, external_reference_map, nullptr)                          \
+  V(base::HashMap*, root_index_map, nullptr)                                  \
+  V(int, pending_microtask_count, 0)                                          \
+  V(HStatistics*, hstatistics, nullptr)                                       \
+  V(CompilationStatistics*, turbo_statistics, nullptr)                        \
+  V(HTracer*, htracer, nullptr)                                               \
+  V(CodeTracer*, code_tracer, nullptr)                                        \
+  V(bool, fp_stubs_generated, false)                                          \
+  V(uint32_t, per_isolate_assert_data, 0xFFFFFFFFu)                           \
+  V(PromiseRejectCallback, promise_reject_callback, nullptr)                  \
+  V(const v8::StartupData*, snapshot_blob, nullptr)                           \
+  V(int, code_and_metadata_size, 0)                                           \
+  V(int, bytecode_and_metadata_size, 0)                                       \
+  /* true if being profiled. Causes collection of extra compile info. */      \
+  V(bool, is_profiling, false)                                                \
   ISOLATE_INIT_SIMULATOR_LIST(V)
 
 #define THREAD_LOCAL_TOP_ACCESSOR(type, name)                        \