Add map-based read barrier to WeakCell

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index 4e7cf8f1dfb20faf28f30c3d9e861cf57fe773ba..2ac457d4495bd78ac1ce74531d098811bcab07c6 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -9,6 +9,7 @@
 #include "src/heap/objects-visiting.h"
 #include "src/jsregexp.h"
 #include "src/macro-assembler.h"
+#include "src/objects-inl.h"
 #include "src/ostreams.h"
 
 namespace v8 {
@@ -647,7 +648,8 @@ void PropertyCell::PropertyCellVerify() {
 
 void WeakCell::WeakCellVerify() {
   CHECK(IsWeakCell());
-  VerifyObjectField(kValueOffset);
+  Object* value = ValueNoReadBarrier();
+  VerifyPointer(value);
   VerifyObjectField(kNextOffset);
 }
 
@@ -1243,7 +1245,7 @@ bool CanLeak(Object* obj, Heap* heap, bool skip_weak_cell) {
   if (!obj->IsHeapObject()) return false;
   if (obj->IsWeakCell()) {
     if (skip_weak_cell) return false;
-    return CanLeak(WeakCell::cast(obj)->value(), heap, skip_weak_cell);
+    return CanLeak(WeakCell::cast(obj)->value(heap), heap, skip_weak_cell);
   }
   if (obj->IsCell()) {
     return CanLeak(Cell::cast(obj)->value(), heap, skip_weak_cell);