Oilpan: Introduce WeakProcessingVisitor

Source/platform/heap/Visitor.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 312 matching lines @@
 // with the object as an argument. Tracing objects will mark all of the
 // contained pointers and push them on the marking stack.
 class PLATFORM_EXPORT Visitor : public VisitorHelper<Visitor> {
 public:
     friend class VisitorHelper<Visitor>;
     friend class InlinedGlobalMarkingVisitor;
 
     enum MarkingMode {
         GlobalMarking,
         ThreadLocalMarking,
+        WeakProcessing,
     };
 
     virtual ~Visitor() { }
 
     using VisitorHelper<Visitor>::mark;
 
     // This method marks an object and adds it to the set of objects
     // that should have their trace method called. Since not all
     // objects have vtables we have to have the callback as an
     // explicit argument, but we can use the templated one-argument
@@ skipping 42 matching lines @@
     virtual bool ensureMarked(const void*) = 0;
 
 #if ENABLE(GC_PROFILING)
     void setHostInfo(void* object, const String& name)
     {
         m_hostObject = object;
         m_hostName = name;
     }
 #endif
 
-    inline bool isGlobalMarkingVisitor() const { return m_isGlobalMarkingVisitor; }
+    inline MarkingMode markingMode() const { return m_markingMode; }
 
 protected:
     explicit Visitor(MarkingMode markingMode)
-        : m_isGlobalMarkingVisitor(markingMode == GlobalMarking)
+        : m_markingMode(markingMode)
     { }
 
     virtual void registerWeakCellWithCallback(void**, WeakCallback) = 0;
 #if ENABLE(GC_PROFILING)
     virtual void recordObjectGraphEdge(const void*) = 0;
 
     void* m_hostObject;
     String m_hostName;
 #endif
 
 #if ENABLE(ASSERT)
     virtual void checkMarkingAllowed() { }
 #endif
 
 private:
     static Visitor* fromHelper(VisitorHelper<Visitor>* helper) { return static_cast<Visitor*>(helper); }
 
+    const MarkingMode m_markingMode;
     bool m_isGlobalMarkingVisitor;
 };
 
 #if ENABLE(GC_PROFILING)
 template<typename T>
 struct TypenameStringTrait {
     static const String& get()
     {
         DEFINE_STATIC_LOCAL(String, typenameString, (WTF::extractTypeNameFromFunctionName(WTF::extractNameFunction<T>())));
         return typenameString;
     }
 };
 #endif
 
 } // namespace blink
 
 #endif // Visitor_h