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diff --git a/deps/v8/src/objects/js-promise.h b/deps/v8/src/objects/js-promise.h
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+// Copyright 2018 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.
+
+#ifndef V8_OBJECTS_JS_PROMISE_H_
+#define V8_OBJECTS_JS_PROMISE_H_
+
+#include "src/objects.h"
+#include "src/objects/promise.h"
+
+// Has to be the last include (doesn't have include guards):
+#include "src/objects/object-macros.h"
+
+namespace v8 {
+namespace internal {
+
+// Representation of promise objects in the specification. Our layout of
+// JSPromise differs a bit from the layout in the specification, for example
+// there's only a single list of PromiseReaction objects, instead of separate
+// lists for fulfill and reject reactions. The PromiseReaction carries both
+// callbacks from the start, and is eventually morphed into the proper kind of
+// PromiseReactionJobTask when the JSPromise is settled.
+//
+// We also overlay the result and reactions fields on the JSPromise, since
+// the reactions are only necessary for pending promises, whereas the result
+// is only meaningful for settled promises.
+class JSPromise : public JSObject {
+ public:
+  // [reactions_or_result]: Smi 0 terminated list of PromiseReaction objects
+  // in case the JSPromise was not settled yet, otherwise the result.
+  DECL_ACCESSORS(reactions_or_result, Object)
+
+  // [result]: Checks that the promise is settled and returns the result.
+  inline Object* result() const;
+
+  // [reactions]: Checks that the promise is pending and returns the reactions.
+  inline Object* reactions() const;
+
+  DECL_INT_ACCESSORS(flags)
+
+  // [has_handler]: Whether this promise has a reject handler or not.
+  DECL_BOOLEAN_ACCESSORS(has_handler)
+
+  // [handled_hint]: Whether this promise will be handled by a catch
+  // block in an async function.
+  DECL_BOOLEAN_ACCESSORS(handled_hint)
+
+  static const char* Status(Promise::PromiseState status);
+  Promise::PromiseState status() const;
+  void set_status(Promise::PromiseState status);
+
+  // ES section #sec-fulfillpromise
+  static Handle<Object> Fulfill(Handle<JSPromise> promise,
+                                Handle<Object> value);
+  // ES section #sec-rejectpromise
+  static Handle<Object> Reject(Handle<JSPromise> promise, Handle<Object> reason,
+                               bool debug_event = true);
+  // ES section #sec-promise-resolve-functions
+  MUST_USE_RESULT static MaybeHandle<Object> Resolve(Handle<JSPromise> promise,
+                                                     Handle<Object> resolution);
+
+  // This is a helper that extracts the JSPromise from the input
+  // {object}, which is used as a payload for PromiseReaction and
+  // PromiseReactionJobTask.
+  MUST_USE_RESULT static MaybeHandle<JSPromise> From(Handle<HeapObject> object);
+
+  DECL_CAST(JSPromise)
+
+  // Dispatched behavior.
+  DECL_PRINTER(JSPromise)
+  DECL_VERIFIER(JSPromise)
+
+  // Layout description.
+  static const int kReactionsOrResultOffset = JSObject::kHeaderSize;
+  static const int kFlagsOffset = kReactionsOrResultOffset + kPointerSize;
+  static const int kSize = kFlagsOffset + kPointerSize;
+  static const int kSizeWithEmbedderFields =
+      kSize + v8::Promise::kEmbedderFieldCount * kPointerSize;
+
+  // Flags layout.
+  // The first two bits store the v8::Promise::PromiseState.
+  static const int kStatusBits = 2;
+  static const int kHasHandlerBit = 2;
+  static const int kHandledHintBit = 3;
+
+  static const int kStatusShift = 0;
+  static const int kStatusMask = 0x3;
+  STATIC_ASSERT(v8::Promise::kPending == 0);
+  STATIC_ASSERT(v8::Promise::kFulfilled == 1);
+  STATIC_ASSERT(v8::Promise::kRejected == 2);
+
+ private:
+  // ES section #sec-triggerpromisereactions
+  static Handle<Object> TriggerPromiseReactions(Isolate* isolate,
+                                                Handle<Object> reactions,
+                                                Handle<Object> argument,
+                                                PromiseReaction::Type type);
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#include "src/objects/object-macros-undef.h"
+
+#endif  // V8_OBJECTS_JS_PROMISE_H_