Relax heap size assert during compaction

src/heap/spaces.cc

 // Copyright 2011 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/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen.h"
 #include "src/heap/mark-compact.h"
@@ skipping 999 matching lines @@
     if ((cur <= addr) && (addr < next)) return obj;
   }
 
   UNREACHABLE();
   return Smi::FromInt(0);
 }
 
 
 bool PagedSpace::CanExpand() {
   DCHECK(max_capacity_ % AreaSize() == 0);
-  DCHECK(Capacity() <= heap()->MaxOldGenerationSize());
+  DCHECK(heap()->mark_compact_collector()->is_compacting() ||
+         Capacity() <= heap()->MaxOldGenerationSize());
   DCHECK(heap()->CommittedOldGenerationMemory() <=
          heap()->MaxOldGenerationSize() +
              PagedSpace::MaxEmergencyMemoryAllocated());
 
   // Are we going to exceed capacity for this space?
   if (!heap()->CanExpandOldGeneration(Page::kPageSize)) return false;
 
   return true;
 }
 
@@ skipping 2111 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }
 }  // namespace v8::internal