Lend LSan a hand and clear out singleton static persistents first.

third_party/WebKit/Source/platform/heap/PersistentNode.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/heap/PersistentNode.h"
 
 #include "base/debug/alias.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
@@ skipping 39 matching lines @@
     m_freeListHead = node;
     ASSERT(node->isUnused());
   }
   slots->m_next = m_slots;
   m_slots = slots;
 }
 
 void PersistentRegion::releasePersistentNode(
     PersistentNode* persistentNode,
     ThreadState::PersistentClearCallback callback) {
-  ASSERT(!persistentNode->isUnused());
+  DCHECK(callback);
+  DCHECK(!persistentNode->isUnused());
   // 'self' is in use, containing the persistent wrapper object.
-  void* self = persistentNode->self();
-  if (callback) {
-    (*callback)(self);
-    ASSERT(persistentNode->isUnused());
-    return;
-  }
-  Persistent<DummyGCBase>* persistent =
-      reinterpret_cast<Persistent<DummyGCBase>*>(self);
-  persistent->clear();
-  ASSERT(persistentNode->isUnused());
+  (*callback)(persistentNode->self(), ThreadState::ReleasePersistent);
+  DCHECK(persistentNode->isUnused());
 }
 
+#if defined(LEAK_SANITIZER)
+void PersistentRegion::clearPersistentNode(
+    PersistentNode* persistentNode,
+    ThreadState::PersistentClearCallback callback) {
+  DCHECK(callback);
+  DCHECK(!persistentNode->isUnused());
+  // 'self' is in use, containing the persistent wrapper object.
+  (*callback)(persistentNode->self(), ThreadState::ClearPersistent);
+  // Cleared, not freed, so still usable.
+  DCHECK(!persistentNode->isUnused());
+}
+#endif
+
 // This function traces all PersistentNodes. If we encounter
 // a PersistentNodeSlot that contains only freed PersistentNodes,
 // we delete the PersistentNodeSlot. This function rebuilds the free
 // list of PersistentNodes.
 void PersistentRegion::tracePersistentNodes(Visitor* visitor,
                                             ShouldTraceCallback shouldTrace) {
   size_t debugMarkedObjectSize = ProcessHeap::totalMarkedObjectSize();
   base::debug::Alias(&debugMarkedObjectSize);
 
   m_freeListHead = nullptr;
@@ skipping 109 matching lines @@
       }
     }
   }
 #if DCHECK_IS_ON()
   DCHECK_EQ(persistentCount, m_persistentRegion->m_persistentCount);
 #endif
 }
 #endif
 
 }  // namespace blink