make SkRefCnt::getRefCnt() debug-only, remove it from SkNVRefCnt.

include/core/SkRefCnt.h

Index: include/core/SkRefCnt.h
diff --git a/include/core/SkRefCnt.h b/include/core/SkRefCnt.h
index d85c20ecaf0638c233f38810ceb5581001208b77..7ccfbf9d70632798321778e1a3382fa3e7aadf79 100644
--- a/include/core/SkRefCnt.h
+++ b/include/core/SkRefCnt.h
@@ -42,8 +42,10 @@ public:
 #endif
     }
 
+#ifdef SK_DEBUG
     /** Return the reference count. Use only for debugging. */
     int32_t getRefCnt() const { return fRefCnt; }
+#endif
 
     /** May return true if the caller is the only owner.
      *  Ensures that all previous owner's actions are complete.
@@ -269,7 +271,6 @@ public:
         }
     }
     void  deref() const { this->unref(); }  // Chrome prefers to call deref().
-    int32_t getRefCnt() const { return fRefCnt; } // Used by Chrome unit tests.
 
 protected:
 #ifdef SK_DEBUG