When adjusting page's live bytes counter from the mutator adjust owners unswept free bytes counter.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 69e5161ce518e50482bebefe1325ae5d4e6d24fc..90a8d3e1b843caa04ec42c00cc04457c13364c5c 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -411,7 +411,7 @@ static FixedArray* LeftTrimFixedArray(Heap* heap,
   int size_delta = to_trim * kPointerSize;
   if (heap->marking()->TransferMark(elms->address(),
                                     elms->address() + size_delta)) {
-    MemoryChunk::IncrementLiveBytes(elms->address(), -size_delta);
+    MemoryChunk::IncrementLiveBytesFromMutator(elms->address(), -size_delta);
   }
 
   return FixedArray::cast(HeapObject::FromAddress(