Add NativeHandle, a refcounted C++ wrapper around a native_handle_t*

Change-Id: I232dfa2ad2e4a463a39e2e901e4097dffe278cc3
diff --git a/libutils/Android.mk b/libutils/Android.mk
index 1710d36..8e9dfd3 100644
--- a/libutils/Android.mk
+++ b/libutils/Android.mk
@@ -26,6 +26,7 @@
 	LinearAllocator.cpp \
 	LinearTransform.cpp \
 	Log.cpp \
+	NativeHandle.cpp \
 	Printer.cpp \
 	ProcessCallStack.cpp \
 	PropertyMap.cpp \