Report promise reject with no handler (behind a flag).

src/objects.h

 // Copyright 2012 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_H_
 #define V8_OBJECTS_H_
 
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/bailout-reason.h"
@@ skipping 7637 matching lines @@
 // prevent leaking information to user code called during error
 // formatting.
 class JSMessageObject: public JSObject {
  public:
   // [type]: the type of error message.
   DECL_ACCESSORS(type, String)
 
   // [arguments]: the arguments for formatting the error message.
   DECL_ACCESSORS(arguments, JSArray)
 
+  // [promise]: the promise (if any) associated to the error message.
+  DECL_ACCESSORS(promise, Object)
+
   // [script]: the script from which the error message originated.
   DECL_ACCESSORS(script, Object)
 
   // [stack_frames]: an array of stack frames for this error object.
   DECL_ACCESSORS(stack_frames, Object)
 
   // [start_position]: the start position in the script for the error message.
   inline int start_position() const;
   inline void set_start_position(int value);
 
   // [end_position]: the end position in the script for the error message.
   inline int end_position() const;
   inline void set_end_position(int value);
 
   DECLARE_CAST(JSMessageObject)
 
   // Dispatched behavior.
   DECLARE_PRINTER(JSMessageObject)
   DECLARE_VERIFIER(JSMessageObject)
 
   // Layout description.
   static const int kTypeOffset = JSObject::kHeaderSize;
   static const int kArgumentsOffset = kTypeOffset + kPointerSize;
-  static const int kScriptOffset = kArgumentsOffset + kPointerSize;
+  static const int kPromiseOffset = kArgumentsOffset + kPointerSize;
+  static const int kScriptOffset = kPromiseOffset + kPointerSize;
   static const int kStackFramesOffset = kScriptOffset + kPointerSize;
   static const int kStartPositionOffset = kStackFramesOffset + kPointerSize;
   static const int kEndPositionOffset = kStartPositionOffset + kPointerSize;
   static const int kSize = kEndPositionOffset + kPointerSize;
 
   typedef FixedBodyDescriptor<HeapObject::kMapOffset,
                               kStackFramesOffset + kPointerSize,
                               kSize> BodyDescriptor;
 };
 
@@ skipping 3111 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_