[heap] Fix address space leak in Unmapper

src/heap/incremental-marking.h

 // 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.
 
 #ifndef V8_HEAP_INCREMENTAL_MARKING_H_
 #define V8_HEAP_INCREMENTAL_MARKING_H_
 
 #include "src/cancelable-task.h"
 #include "src/execution.h"
 #include "src/heap/heap.h"
 #include "src/heap/incremental-marking-job.h"
 #include "src/heap/mark-compact.h"
 #include "src/heap/spaces.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
 class MarkBit;
 class PagedSpace;
 
 enum class StepOrigin { kV8, kTask };
 
-class IncrementalMarking {
+class V8_EXPORT_PRIVATE IncrementalMarking {
  public:
   enum State { STOPPED, SWEEPING, MARKING, COMPLETE };
 
   enum CompletionAction { GC_VIA_STACK_GUARD, NO_GC_VIA_STACK_GUARD };
 
   enum ForceCompletionAction { FORCE_COMPLETION, DO_NOT_FORCE_COMPLETION };
 
   enum GCRequestType { NONE, COMPLETE_MARKING, FINALIZATION };
 
   explicit IncrementalMarking(Heap* heap);
@@ skipping 269 matching lines @@
   IncrementalMarkingJob incremental_marking_job_;
   Observer new_generation_observer_;
   Observer old_generation_observer_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_H_