Add plumbing in blink to allow overriding the skia font manager.

skia/config/sk_ref_cnt_ext_debug.h

 // Copyright 2013 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 SK_REF_CNT_EXT_DEBUG_H_
 #define SK_REF_CNT_EXT_DEBUG_H_
 
 #ifdef SK_REF_CNT_EXT_RELEASE_H_
 #error Only one SkRefCnt should be used.
 #endif
 
 #include <atomic>
 
+class SkRefCnt;
+
+namespace WTF {
+  void adopted(const SkRefCnt*);
+  void requireAdoption(const SkRefCnt*);
+}
+
 // Alternate implementation of SkRefCnt for Chromium debug builds
 class SK_API SkRefCnt : public SkRefCntBase {
 public:
   SkRefCnt();
   ~SkRefCnt() override;
   void ref() const { SkASSERT(flags_.load() != AdoptionRequired_Flag); SkRefCntBase::ref(); }
+  void deref() const { SkRefCntBase::unref(); }
+private:

[Ilya Kulshin, 2016/02/11 20:40:18]

Note: the actual change here is moving adopted() and requireAdoption() to be
private. deref() is unchanged.

   void adopted() const { flags_ |= Adopted_Flag; }
   void requireAdoption() const { flags_ |= AdoptionRequired_Flag; }
-  void deref() const { SkRefCntBase::unref(); }
-private:
 
   enum {
     Adopted_Flag = 0x1,
     AdoptionRequired_Flag = 0x2,
   };
 
   mutable std::atomic<int> flags_;
+
+  friend void WTF::adopted(const SkRefCnt*);
+  friend void WTF::requireAdoption(const SkRefCnt*);
 };
 
 inline SkRefCnt::SkRefCnt() : flags_(0) { }
 
 inline SkRefCnt::~SkRefCnt() { }
 
 // Bootstrap for Blink's WTF::RefPtr
 
 namespace WTF {
   inline void adopted(const SkRefCnt* object) {
     if (!object)
       return;
     object->adopted();
   }
   inline void requireAdoption(const SkRefCnt* object) {
     if (!object)
       return;
     object->requireAdoption();
   }
 };
 
-using WTF::adopted;
-using WTF::requireAdoption;
-
 #endif