Add GrResource base class for ibs, texs, vbs, etc.
Add lostContext() to GrContext.

Review URL: http://codereview.appspot.com/4328044/



git-svn-id: http://skia.googlecode.com/svn/trunk@1026 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrRefCnt.h b/gpu/include/GrRefCnt.h
index c462b2c..9c9fed1 100644
--- a/gpu/include/GrRefCnt.h
+++ b/gpu/include/GrRefCnt.h
@@ -104,6 +104,14 @@
     dst = src;
 }
 
+template<typename T>
+static inline void GrSafeSetNull(T*& obj) {
+    if (NULL != obj) {
+        obj->unref();
+        obj = NULL;
+    }
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 class GrAutoRef : GrNoncopyable {