diff --git a/deps/v8/src/heap/incremental-marking.cc b/deps/v8/src/heap/incremental-marking.cc
index 58eb0aa..b2b796f 100644
--- a/deps/v8/src/heap/incremental-marking.cc
+++ b/deps/v8/src/heap/incremental-marking.cc
@@ -364,7 +364,7 @@ void IncrementalMarking::DeactivateIncrementalWriteBarrier() {
   DeactivateIncrementalWriteBarrierForSpace(heap_->new_space());
 
   LargePage* lop = heap_->lo_space()->first_page();
-  while (lop->is_valid()) {
+  while (LargePage::IsValid(lop)) {
     SetOldSpacePageFlags(lop, false, false);
     lop = lop->next_page();
   }
@@ -396,7 +396,7 @@ void IncrementalMarking::ActivateIncrementalWriteBarrier() {
   ActivateIncrementalWriteBarrier(heap_->new_space());
 
   LargePage* lop = heap_->lo_space()->first_page();
-  while (lop->is_valid()) {
+  while (LargePage::IsValid(lop)) {
     SetOldSpacePageFlags(lop, true, is_compacting_);
     lop = lop->next_page();
   }
diff --git a/deps/v8/src/heap/spaces-inl.h b/deps/v8/src/heap/spaces-inl.h
index c2c4d12..d63ee63 100644
--- a/deps/v8/src/heap/spaces-inl.h
+++ b/deps/v8/src/heap/spaces-inl.h
@@ -155,7 +155,7 @@ Page* Page::Initialize(Heap* heap, MemoryChunk* chunk, Executability executable,
 
 bool PagedSpace::Contains(Address addr) {
   Page* p = Page::FromAddress(addr);
-  if (!p->is_valid()) return false;
+  if (!Page::IsValid(p)) return false;
   return p->owner() == this;
 }
 
diff --git a/deps/v8/src/heap/spaces.cc b/deps/v8/src/heap/spaces.cc
index 0806b25..c0e109b 100644
--- a/deps/v8/src/heap/spaces.cc
+++ b/deps/v8/src/heap/spaces.cc
@@ -2953,7 +2953,7 @@ LargePage* LargeObjectSpace::FindPage(Address a) {
   if (e != NULL) {
     DCHECK(e->value != NULL);
     LargePage* page = reinterpret_cast<LargePage*>(e->value);
-    DCHECK(page->is_valid());
+    DCHECK(LargePage::IsValid(page));
     if (page->Contains(a)) {
       return page;
     }
diff --git a/deps/v8/src/heap/spaces.h b/deps/v8/src/heap/spaces.h
index 3461de3..e35c057 100644
--- a/deps/v8/src/heap/spaces.h
+++ b/deps/v8/src/heap/spaces.h
@@ -278,9 +278,9 @@ class MemoryChunk {
   // Only works for addresses in pointer spaces, not data or code spaces.
   static inline MemoryChunk* FromAnyPointerAddress(Heap* heap, Address addr);
 
-  Address address() { return reinterpret_cast<Address>(this); }
+  static bool IsValid(MemoryChunk* chunk) { return chunk != nullptr; }
 
-  bool is_valid() { return address() != NULL; }
+  Address address() { return reinterpret_cast<Address>(this); }
 
   MemoryChunk* next_chunk() const {
     return reinterpret_cast<MemoryChunk*>(base::Acquire_Load(&next_chunk_));