[wasm] structured cloning opt-out flag

src/value-serializer.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/value-serializer.h"
 
 #include <type_traits>
 
 #include "src/base/logging.h"
 #include "src/conversions.h"
@@ skipping 400 matching lines @@
   STACK_CHECK(isolate_, Nothing<bool>());
 
   HandleScope scope(isolate_);
   switch (instance_type) {
     case JS_ARRAY_TYPE:
       return WriteJSArray(Handle<JSArray>::cast(receiver));
     case JS_OBJECT_TYPE:
     case JS_API_OBJECT_TYPE: {
       Handle<JSObject> js_object = Handle<JSObject>::cast(receiver);
       Map* map = js_object->map();
-      if (FLAG_expose_wasm &&
+      if (!FLAG_wasm_disable_structured_cloning &&
           map->GetConstructor() ==
               isolate_->native_context()->wasm_module_constructor()) {
         return WriteWasmModule(js_object);
       } else if (JSObject::GetInternalFieldCount(map)) {
         return WriteHostObject(js_object);
       } else {
         return WriteJSObject(js_object);
       }
     }
     case JS_SPECIAL_API_OBJECT_TYPE:
@@ skipping 1093 matching lines @@
     return MaybeHandle<JSArrayBufferView>();
   }
   Handle<JSTypedArray> typed_array = isolate_->factory()->NewJSTypedArray(
       external_array_type, buffer, byte_offset, byte_length / element_size,
       pretenure_);
   AddObjectWithID(id, typed_array);
   return typed_array;
 }
 
 MaybeHandle<JSObject> ValueDeserializer::ReadWasmModule() {
-  if (!FLAG_expose_wasm) return MaybeHandle<JSObject>();
+  if (FLAG_wasm_disable_structured_cloning) return MaybeHandle<JSObject>();
 
   Vector<const uint8_t> encoding_tag;
   if (!ReadRawBytes(sizeof(WasmEncodingTag)).To(&encoding_tag) ||
       encoding_tag[0] != static_cast<uint8_t>(WasmEncodingTag::kRawBytes)) {
     return MaybeHandle<JSObject>();
   }
 
   // Extract the data from the buffer: wasm wire bytes, followed by V8 compiled
   // script data.
   static_assert(sizeof(int) <= sizeof(uint32_t),
@@ skipping 333 matching lines @@
   if (stack.size() != 1) {
     isolate_->Throw(*isolate_->factory()->NewError(
         MessageTemplate::kDataCloneDeserializationError));
     return MaybeHandle<Object>();
   }
   return scope.CloseAndEscape(stack[0]);
 }
 
 }  // namespace internal
 }  // namespace v8