Allow users to build on top of, instead of beneath, SkRefCnt.

Alternative to r11811.

The Chromium half of this can be seen at https://codereview.chromium.org/40973002/ .

R=reed@google.com

Review URL: https://codereview.chromium.org/40503002

git-svn-id: http://skia.googlecode.com/svn/trunk/src@11967 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/core/SkRefCnt.cpp b/core/SkRefCnt.cpp
index 78f9cb2..b922e03 100644
--- a/core/SkRefCnt.cpp
+++ b/core/SkRefCnt.cpp
@@ -9,10 +9,5 @@
 #include "SkRefCnt.h"
 #include "SkWeakRefCnt.h"
 
-SK_DEFINE_INST_COUNT(SkRefCnt)
+SK_DEFINE_INST_COUNT(SkRefCntBase)
 SK_DEFINE_INST_COUNT(SkWeakRefCnt)
-
-#ifdef SK_BUILD_FOR_WIN
-SkRefCnt::SkRefCnt(const SkRefCnt&) { }
-SkRefCnt& SkRefCnt::operator=(const SkRefCnt&) { return *this; }
-#endif