Oilpan: Remove checkMarkingAllowed

Source/platform/heap/MarkingVisitorImpl.h

 // Copyright 2014 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 MarkingVisitorImpl_h
 #define MarkingVisitorImpl_h
 
 #include "platform/heap/Heap.h"
 #include "platform/heap/ThreadState.h"
 #include "platform/heap/Visitor.h"
@@ skipping 21 matching lines @@
         // the dangling pointer.
         // Release builds don't have the ASSERT, but it is OK because
         // release builds will crash in the following header->isMarked()
         // because all the entries of the orphaned heaps are zapped.
         ASSERT(!pageFromObject(objectPointer)->orphaned());
 
         if (header->isMarked())
             return;
 
 #if ENABLE(ASSERT)
-        toDerived()->checkMarkingAllowed();
+        ASSERT(ThreadState::current()->isInGC());
         ASSERT(Heap::findPageFromAddress(header));
 #endif
         header->mark();
 
 #if ENABLE(GC_PROFILING)
         toDerived()->recordObjectGraphEdge(objectPointer);
 #endif
 
         if (callback)
             Heap::pushTraceCallback(const_cast<void*>(objectPointer), callback);
@@ skipping 65 matching lines @@
 private:
     static void markNoTracingCallback(Visitor* visitor, void* object)
     {
         visitor->markNoTracing(object);
     }
 };
 
 } // namespace blink
 
 #endif