[heap] Assert that there's no recodred slot corresponding to unboxed double field.

src/heap/heap.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_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 1154 matching lines @@
   void RecordWriteIntoCodeSlow(Code* host, RelocInfo* rinfo, Object* target);
   void RecordWritesIntoCode(Code* code);
   inline void RecordFixedArrayElements(FixedArray* array, int offset,
                                        int length);
 
   inline Address* store_buffer_top_address();
 
   void ClearRecordedSlot(HeapObject* object, Object** slot);
   void ClearRecordedSlotRange(Address start, Address end);
 
+  bool HasRecordedSlot(HeapObject* object, Object** slot);
+
   // ===========================================================================
   // Incremental marking API. ==================================================
   // ===========================================================================
 
   // Start incremental marking and ensure that idle time handler can perform
   // incremental steps.
   void StartIdleIncrementalMarking(GarbageCollectionReason gc_reason);
 
   // Starts incremental marking assuming incremental marking is currently
   // stopped.
@@ skipping 1458 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_