Oilpan: handle thread-local weak tracing slightly better.

Source/platform/heap/TraceTraits.h

 // 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.
 
 #ifndef TraceTraits_h
 #define TraceTraits_h
 
 #include "platform/heap/GCInfo.h"
 #include "platform/heap/Heap.h"
 #include "platform/heap/Visitor.h"
@@ skipping 38 matching lines @@
             // unbounded system stack usage they can bring about.
             //
             // Assert against deep stacks so as to flush them out,
             // but test and appropriately handle them should they occur
             // in release builds.
             //
             // ASan adds extra stack usage, so disable the assert when it is
             // enabled so as to avoid testing against a much lower & too low,
             // stack depth threshold.
 #if !defined(ADDRESS_SANITIZER)
-            ASSERT(StackFrameDepth::isSafeToRecurse());
+            ASSERT(!StackFrameDepth::isEnabled() || StackFrameDepth::isSafeToRecurse());
 #endif
             if (LIKELY(StackFrameDepth::isSafeToRecurse())) {
                 if (visitor->ensureMarked(t)) {
                     TraceTrait<T>::trace(visitor, const_cast<T*>(t));
                 }
                 return;
             }
         }
         visitor->mark(const_cast<T*>(t), &TraceTrait<T>::trace);
     }
@@ skipping 479 matching lines @@
         // since iterating over the hash table backing will find the whole
         // chain.
         visitor->markNoTracing(node);
         return false;
     }
 };
 
 } // namespace WTF
 
 #endif