Added initial implementation of filter for MTP updates.

Telegram/SourceFiles/api/api_filter_updates.h

@@ -0,0 +1,27 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+namespace Api {
+
+template <typename Type>
+void PerformForUpdate(
+		const MTPUpdates &updates,
+		Fn<void(const Type &)> callback) {
+	updates.match([&](const MTPDupdates &updates) {
+		for (const auto &update : updates.vupdates().v) {
+			update.match([&](const Type &d) {
+				callback(d);
+			}, [](const auto &) {
+			});
+		}
+	}, [](const auto &) {
+	});
+}
+
+} // namespace Api