Assert sequence validity on non-thread-safe RefCount manipulations (2)

base/memory/ref_counted.cc

Index: base/memory/ref_counted.cc
diff --git a/base/memory/ref_counted.cc b/base/memory/ref_counted.cc
index 46bbd7ad858b152ec8a29d1b5060c24fb466be09..b6c888dcc0cbfb3ef829ffeb538b22cadc7ff72d 100644
--- a/base/memory/ref_counted.cc
+++ b/base/memory/ref_counted.cc
@@ -3,9 +3,17 @@
 // found in the LICENSE file.
 
 #include "base/memory/ref_counted.h"
+
 #include "base/threading/thread_collision_warner.h"
 
 namespace base {
+namespace {
+
+#if DCHECK_IS_ON()
+AtomicRefCount g_cross_thread_ref_count_access_allow_count = 0;
+#endif
+
+}  // namespace
 
 namespace subtle {
 
@@ -43,6 +51,23 @@ bool RefCountedThreadSafeBase::Release() const {
   return false;
 }
 
+#if DCHECK_IS_ON()
+bool RefCountedBase::CalledOnValidSequence() const {
+  return sequence_checker_.CalledOnValidSequence() ||
+         !AtomicRefCountIsZero(&g_cross_thread_ref_count_access_allow_count);
+}
+#endif
+
 }  // namespace subtle
 
+#if DCHECK_IS_ON()
+ScopedAllowCrossThreadRefCountAccess::ScopedAllowCrossThreadRefCountAccess() {
+  AtomicRefCountInc(&g_cross_thread_ref_count_access_allow_count);
+}
+
+ScopedAllowCrossThreadRefCountAccess::~ScopedAllowCrossThreadRefCountAccess() {
+  AtomicRefCountDec(&g_cross_thread_ref_count_access_allow_count);
+}
+#endif
+
 }  // namespace base