Fix memory leaks.

http://codereview.appspot.com/6301098/



git-svn-id: http://skia.googlecode.com/svn/trunk@4281 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrSamplerState.h b/include/gpu/GrSamplerState.h
index f8ad1c0..1f81afa 100644
--- a/include/gpu/GrSamplerState.h
+++ b/include/gpu/GrSamplerState.h
@@ -81,8 +81,7 @@
         fSwapRAndB = s.fSwapRAndB;
         fTextureDomain = s.fTextureDomain;
 
-        fCustomStage = s.fCustomStage;
-        SkSafeRef(fCustomStage);
+        GrSafeAssign(fCustomStage, s.fCustomStage);
 
         return *this;
     }