Introduce exception object and remove some uses of MaybeObject::IsFailure().

src/elements.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 578 matching lines @@
 
   virtual ElementsKind kind() const V8_FINAL V8_OVERRIDE {
     return ElementsTraits::Kind;
   }
 
   static void ValidateContents(Handle<JSObject> holder, int length) {
   }
 
   static void ValidateImpl(Handle<JSObject> holder) {
     Handle<FixedArrayBase> fixed_array_base(holder->elements());
-    // When objects are first allocated, its elements are Failures.
-    if (fixed_array_base->IsFailure()) return;
     if (!fixed_array_base->IsHeapObject()) return;
     // Arrays that have been shifted in place can't be verified.
     if (fixed_array_base->IsFiller()) return;
     int length = 0;
     if (holder->IsJSArray()) {
       Object* length_obj = Handle<JSArray>::cast(holder)->length();
       if (length_obj->IsSmi()) {
         length = Smi::cast(length_obj)->value();
       }
     } else {
@@ skipping 1405 matching lines @@
       UNREACHABLE();
       break;
   }
 
   array->set_elements(*elms);
   array->set_length(Smi::FromInt(number_of_elements));
   return array;
 }
 
 } }  // namespace v8::internal