Fix crash in session destruction.

Also use rpl::event_stream for downloaderTaskFinished.

Telegram/SourceFiles/boxes/add_contact_box.cpp

@@ -1364,7 +1364,10 @@ void RevokePublicLinkBox::prepare() {
 
 	addButton(tr::lng_cancel(), [=] { closeBox(); });
 
-	subscribe(_session->downloaderTaskFinished(), [=] { update(); });
+	_session->downloaderTaskFinished(
+	) | rpl::start_with_next([=] {
+		update();
+	}, lifetime());
 
 	_inner->resizeToWidth(st::boxWideWidth);
 	setDimensions(st::boxWideWidth, _innerTop + _inner->height());

Telegram/SourceFiles/boxes/background_box.cpp

@@ -203,7 +203,10 @@ BackgroundBox::Inner::Inner(
 	}
 	requestPapers();
 
-	subscribe(_session->downloaderTaskFinished(), [=] { update(); });
+	_session->downloaderTaskFinished(
+	) | rpl::start_with_next([=] {
+		update();
+	}, lifetime());
 	using Update = Window::Theme::BackgroundUpdate;
 	subscribe(Window::Theme::Background(), [=](const Update &update) {
 		if (update.paletteChanged()) {

Telegram/SourceFiles/boxes/background_preview_box.cpp

@@ -419,9 +419,10 @@ BackgroundPreviewBox::BackgroundPreviewBox(
 	if (_media) {
 		_media->thumbnailWanted(_paper.fileOrigin());
 	}
-	subscribe(_controller->session().downloaderTaskFinished(), [=] {
+	_controller->session().downloaderTaskFinished(
+	) | rpl::start_with_next([=] {
 		update();
-	});
+	}, lifetime());
 }
 
 not_null<HistoryView::ElementDelegate*> BackgroundPreviewBox::delegate() {

Telegram/SourceFiles/boxes/confirm_box.cpp

@@ -891,9 +891,10 @@ ConfirmInviteBox::ConfirmInviteBox(
 		_photo = photo->createMediaView();
 		_photo->wanted(Data::PhotoSize::Small, Data::FileOrigin());
 		if (!_photo->image(Data::PhotoSize::Small)) {
-			subscribe(_session->downloaderTaskFinished(), [=] {
+			_session->downloaderTaskFinished(
+			) | rpl::start_with_next([=] {
 				update();
-			});
+			}, lifetime());
 		}
 	} else {
 		_photoEmpty = std::make_unique<Ui::EmptyUserpic>(

Telegram/SourceFiles/boxes/edit_caption_box.cpp

@@ -291,7 +291,8 @@ EditCaptionBox::EditCaptionBox(
 	Assert(_thumbnailImageLoaded || _refreshThumbnail);
 
 	if (!_thumbnailImageLoaded) {
-		subscribe(_controller->session().downloaderTaskFinished(), [=] {
+		_controller->session().downloaderTaskFinished(
+		) | rpl::start_with_next([=] {
 			if (_thumbnailImageLoaded
 				|| (_photoMedia && !_photoMedia->image(PhotoSize::Large))
 				|| (_documentMedia && !_documentMedia->thumbnail())) {
@@ -299,7 +300,7 @@ EditCaptionBox::EditCaptionBox(
 			}
 			_refreshThumbnail();
 			update();
-		});
+		}, lifetime());
 	}
 	_field.create(
 		this,

Telegram/SourceFiles/boxes/peer_list_box.cpp

@@ -662,9 +662,10 @@ PeerListContent::PeerListContent(
 , _st(st)
 , _controller(controller)
 , _rowHeight(_st.item.height) {
-	subscribe(_controller->session().downloaderTaskFinished(), [=] {
+	_controller->session().downloaderTaskFinished(
+	) | rpl::start_with_next([=] {
 		update();
-	});
+	}, lifetime());
 
 	using UpdateFlag = Data::PeerUpdate::Flag;
 	_controller->session().changes().peerUpdates(

Telegram/SourceFiles/boxes/share_box.cpp

@@ -570,9 +570,10 @@ ShareBox::Inner::Inner(
 			update.oldFirstLetters);
 	}, lifetime());
 
-	subscribe(_navigation->session().downloaderTaskFinished(), [=] {
+	_navigation->session().downloaderTaskFinished(
+	) | rpl::start_with_next([=] {
 		update();
-	});
+	}, lifetime());
 
 	subscribe(Window::Theme::Background(), [this](const Window::Theme::BackgroundUpdate &update) {
 		if (update.paletteChanged()) {

Telegram/SourceFiles/boxes/sticker_set_box.cpp

@@ -254,7 +254,10 @@ StickerSetBox::Inner::Inner(
 
 	_controller->session().api().updateStickers();
 
-	subscribe(_controller->session().downloaderTaskFinished(), [this] { update(); });
+	_controller->session().downloaderTaskFinished(
+	) | rpl::start_with_next([=] {
+		update();
+	}, lifetime());
 
 	setMouseTracking(true);
 }

Telegram/SourceFiles/boxes/stickers_box.cpp

@@ -1002,10 +1002,12 @@ Main::Session &StickersBox::Inner::session() const {
 }
 
 void StickersBox::Inner::setup() {
-	subscribe(session().downloaderTaskFinished(), [this] {
+	session().downloaderTaskFinished(
+	) | rpl::start_with_next([=] {
 		update();
 		readVisibleSets();
-	});
+	}, lifetime());
+
 	setMouseTracking(true);
 }