Revert of Remove promotion backup case and report OOM instead.

src/heap/heap.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 2182 matching lines @@
       // try to promote the object.
       if (SemiSpaceCopyObject<alignment>(map, slot, object, object_size)) {
         return;
       }
     }
 
     if (PromoteObject<object_contents, alignment>(map, slot, object,
                                                   object_size)) {
       return;
     }
-    V8::FatalProcessOutOfMemory("Scavenge promotion failed");
+
+    // If promotion failed, we try to copy the object to the other semi-space
+    if (SemiSpaceCopyObject<alignment>(map, slot, object, object_size)) return;
+
+    UNREACHABLE();
   }
 
 
   static inline void EvacuateJSFunction(Map* map, HeapObject** slot,
                                         HeapObject* object) {
     ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
         JSFunction::kSize>(map, slot, object);
 
     MapWord map_word = object->map_word();
     DCHECK(map_word.IsForwardingAddress());
@@ skipping 4306 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal