[promises] Refactor CreatePromise

src/code-stub-assembler.h

 // 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.
 
 #ifndef V8_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 1035 matching lines @@
 
   // TypedArray/ArrayBuffer helpers
   Node* IsDetachedBuffer(Node* buffer);
 
   Node* ElementOffsetFromIndex(Node* index, ElementsKind kind,
                                ParameterMode mode, int base_size = 0);
 
   // Promise helpers
   Node* IsPromiseHookEnabled();
 
+  Node* AllocateJSPromise(Node* context);
+  void PromiseInit(Node* promise);
+
+  // Other promise fields may also be need to set/reset. This only
+  // provides a helper for certain init patterns.
+  void PromiseSet(Node* promise, Node* status, Node* result);
+
  protected:
   void DescriptorLookupLinear(Node* unique_name, Node* descriptors, Node* nof,
                               Label* if_found, Variable* var_name_index,
                               Label* if_not_found);
 
   Node* CallGetterIfAccessor(Node* value, Node* details, Node* context,
                              Node* receiver, Label* if_bailout);
 
   Node* TryToIntptr(Node* key, Label* miss);
 
@@ skipping 91 matching lines @@
   }
 #else
 #define CSA_SLOW_ASSERT(csa, x) ((void)0)
 #endif
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_