Added new Adaptive class to replace legacy Adaptive namespace.

Temporarily named class as AdaptiveModern.

Telegram/SourceFiles/window/window_controller.cpp

@@ -41,6 +41,7 @@ namespace Window {
 
 Controller::Controller()
 : _widget(this)
+, _adaptive(std::make_unique<AdaptiveModern>())
 , _isActiveTimer([=] { updateIsActive(); }) {
 	_widget.init();
 }
@@ -367,4 +368,8 @@ void Controller::showLogoutConfirmation() {
 		callback));
 }
 
+Window::AdaptiveModern &Controller::adaptive() const {
+	return *_adaptive;
+}
+
 } // namespace Window