Fix crash when querying a runtime config that is defined in environment

include/utils/SkRTConf.h

Index: include/utils/SkRTConf.h
diff --git a/include/utils/SkRTConf.h b/include/utils/SkRTConf.h
index ea6e99ed891ec35e17b091f08d9f2e31e2100617..dc1f461b110a417f75113305ff26ebfa097e5e01 100644
--- a/include/utils/SkRTConf.h
+++ b/include/utils/SkRTConf.h
@@ -73,6 +73,9 @@ public:
     void possiblyDumpFile() const;
     void validate() const;
     template <typename T> void set(const char *confname, T value);
+#ifdef SK_SUPPORT_UNITTEST
+    static void UnitTest();
+#endif
 private:
     template<typename T> friend class SkRTConf;
 
@@ -82,6 +85,9 @@ private:
     SkTDArray<SkString *> fConfigFileKeys, fConfigFileValues;
     typedef SkTDict< SkTDArray<SkRTConfBase *> * > ConfMap;
     ConfMap fConfs;
+#ifdef SK_SUPPORT_UNITTEST
+    SkRTConfRegistry(bool);
+#endif
 };
 
 // our singleton registry