Revert of [wasm] WebAssembly.Memory object can be referenced by multiple Instance objects.

src/wasm/wasm-objects.h

Index: src/wasm/wasm-objects.h
diff --git a/src/wasm/wasm-objects.h b/src/wasm/wasm-objects.h
index 8578dc8b4f8dd90cfb1ecddd667f5e1e487d82c7..0ba5a8dc3f516af9355cf8edf5e69a613b4baa30 100644
--- a/src/wasm/wasm-objects.h
+++ b/src/wasm/wasm-objects.h
@@ -17,7 +17,6 @@
 class WasmCompiledModule;
 class WasmDebugInfo;
 class WasmInstanceObject;
-class WasmInstanceWrapper;
 
 #define DECLARE_CASTS(name)             \
   static bool Is##name(Object* object); \
@@ -80,14 +79,12 @@
 class WasmMemoryObject : public JSObject {
  public:
   // TODO(titzer): add the brand as an internal field instead of a property.
-  enum Fields : uint8_t { kArrayBuffer, kMaximum, kInstancesLink, kFieldCount };
+  enum Fields : uint8_t { kArrayBuffer, kMaximum, kInstance, kFieldCount };
 
   DECLARE_CASTS(WasmMemoryObject);
   DECLARE_ACCESSORS(buffer, JSArrayBuffer);
-  DECLARE_OPTIONAL_ACCESSORS(instances_link, WasmInstanceWrapper);
-
-  void AddInstance(Isolate* isolate, Handle<WasmInstanceObject> object);
-  void ResetInstancesLink(Isolate* isolate);
+
+  void AddInstance(WasmInstanceObject* object);
   uint32_t current_pages();
   int32_t maximum_pages();  // returns < 0 if there is no maximum
 
@@ -108,7 +105,6 @@
     kMemoryArrayBuffer,
     kGlobalsArrayBuffer,
     kDebugInfo,
-    kWasmMemInstanceWrapper,
     kFieldCount
   };
 
@@ -119,7 +115,6 @@
   DECLARE_OPTIONAL_ACCESSORS(memory_buffer, JSArrayBuffer);
   DECLARE_OPTIONAL_ACCESSORS(memory_object, WasmMemoryObject);
   DECLARE_OPTIONAL_ACCESSORS(debug_info, WasmDebugInfo);
-  DECLARE_OPTIONAL_ACCESSORS(instance_wrapper, WasmInstanceWrapper);
 
   WasmModuleObject* module_object();
   wasm::WasmModule* module();
@@ -331,61 +326,6 @@
                                     int func_index, int byte_offset);
 };
 
-class WasmInstanceWrapper : public FixedArray {
- public:
-  static Handle<WasmInstanceWrapper> New(Isolate* isolate,
-                                         Handle<WasmInstanceObject> instance);
-  static WasmInstanceWrapper* cast(Object* fixed_array) {
-    SLOW_DCHECK(IsWasmInstanceWrapper(fixed_array));
-    return reinterpret_cast<WasmInstanceWrapper*>(fixed_array);
-  }
-  static bool IsWasmInstanceWrapper(Object* obj);
-  bool has_instance() { return get(kWrapperInstanceObject)->IsWeakCell(); }
-  Handle<WasmInstanceObject> instance_object() {
-    Object* obj = get(kWrapperInstanceObject);
-    DCHECK(obj->IsWeakCell());
-    WeakCell* cell = WeakCell::cast(obj);
-    DCHECK(cell->value()->IsJSObject());
-    return handle(WasmInstanceObject::cast(cell->value()));
-  }
-  bool has_next() { return IsWasmInstanceWrapper(get(kNextInstanceWrapper)); }
-  bool has_previous() {
-    return IsWasmInstanceWrapper(get(kPreviousInstanceWrapper));
-  }
-  void set_instance_object(Handle<JSObject> instance, Isolate* isolate);
-  void set_next_wrapper(Object* obj) {
-    DCHECK(IsWasmInstanceWrapper(obj));
-    set(kNextInstanceWrapper, obj);
-  }
-  void set_previous_wrapper(Object* obj) {
-    DCHECK(IsWasmInstanceWrapper(obj));
-    set(kPreviousInstanceWrapper, obj);
-  }
-  Handle<WasmInstanceWrapper> next_wrapper() {
-    Object* obj = get(kNextInstanceWrapper);
-    DCHECK(IsWasmInstanceWrapper(obj));
-    return handle(WasmInstanceWrapper::cast(obj));
-  }
-  Handle<WasmInstanceWrapper> previous_wrapper() {
-    Object* obj = get(kPreviousInstanceWrapper);
-    DCHECK(IsWasmInstanceWrapper(obj));
-    return handle(WasmInstanceWrapper::cast(obj));
-  }
-  void reset_next_wrapper() { set_undefined(kNextInstanceWrapper); }
-  void reset_previous_wrapper() { set_undefined(kPreviousInstanceWrapper); }
-  void reset() {
-    for (int kID = 0; kID < kWrapperPropertyCount; kID++) set_undefined(kID);
-  }
-
- private:
-  enum {
-    kWrapperInstanceObject,
-    kNextInstanceWrapper,
-    kPreviousInstanceWrapper,
-    kWrapperPropertyCount
-  };
-};
-
 #undef DECLARE_ACCESSORS
 #undef DECLARE_OPTIONAL_ACCESSORS