Add DISALLOW_COPY_AND_ASSIGN macro.

Make the DISALLOW_COPY_AND_ASSIGN macro delete the member functions rather
than just not defining them to improve analysis of the Scoped.. classes.
Add a few missing const qualifiers.

Change-Id: I48eee0c22908d45a05df6979aa61442d2eedcf36
diff --git a/include/nativehelper/JNIHelp.h b/include/nativehelper/JNIHelp.h
index cfab8f7..bf01986 100644
--- a/include/nativehelper/JNIHelp.h
+++ b/include/nativehelper/JNIHelp.h
@@ -172,6 +172,20 @@
     jniLogException(&env->functions, priority, tag, exception);
 }
 
+#if !defined(DISALLOW_COPY_AND_ASSIGN)
+// DISALLOW_COPY_AND_ASSIGN disallows the copy and operator= functions. It goes in the private:
+// declarations in a class.
+#if __cplusplus >= 201103L
+#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&) = delete;  \
+  void operator=(const TypeName&) = delete
+#else
+#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&);  \
+  void operator=(const TypeName&)
+#endif  // __has_feature(cxx_deleted_functions)
+#endif  // !defined(DISALLOW_COPY_AND_ASSIGN)
+
 #endif
 
 /*