v8: fix tracking of longest_step in IncrementalMarking.

src/incremental-marking.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/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 644 matching lines @@
                (obj->IsFiller() && Marking::IsWhite(mark_bit)) ||
                (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR) &&
                 Marking::IsBlack(mark_bit)));
 #endif
     }
   }
   marking_deque_.set_top(new_top);
 
   steps_took_since_last_gc_ = 0;
   steps_count_since_last_gc_ = 0;
-  longest_step_ = 0.0;
 }
 
 
 void IncrementalMarking::VisitObject(Map* map, HeapObject* obj, int size) {
   MarkBit map_mark_bit = Marking::MarkBitFrom(map);
   if (Marking::IsWhite(map_mark_bit)) {
     WhiteToGreyAndPush(map, map_mark_bit);
   }
 
   IncrementalMarkingMarkingVisitor::IterateBody(map, obj);
@@ skipping 313 matching lines @@
   bytes_scanned_ = 0;
   write_barriers_invoked_since_last_step_ = 0;
 }
 
 
 int64_t IncrementalMarking::SpaceLeftInOldSpace() {
   return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSizeOfObjects();
 }
 
 } }  // namespace v8::internal