Build fix for chromium shared component build

BUG=304265
TBR=reed@google.com

Review URL: https://codereview.chromium.org/27082003

git-svn-id: http://skia.googlecode.com/svn/trunk/src@11827 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/core/SkRefCnt.cpp b/core/SkRefCnt.cpp
index 8d09065..cf8923d 100644
--- a/core/SkRefCnt.cpp
+++ b/core/SkRefCnt.cpp
@@ -11,3 +11,8 @@
 
 SK_DEFINE_INST_COUNT(SkRefCnt)
 SK_DEFINE_INST_COUNT(SkWeakRefCnt)
+
+SkRefCnt::SkRefCnt(const SkRefCnt&) { }
+
+SkRefCnt::operator=(const SkRefCnt&) { }
+