Minor cleanups

Pulling out some of the smaller changes that aren't related to the manga controller changes in #7244

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaController.kt

@@ -34,6 +34,7 @@ import com.google.android.material.snackbar.Snackbar
 import dev.chrisbanes.insetter.applyInsetter
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.davidea.flexibleadapter.SelectableAdapter
+import eu.kanade.data.chapter.NoChaptersException
 import eu.kanade.domain.history.model.HistoryWithRelations
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.cache.CoverCache
@@ -84,7 +85,6 @@ import eu.kanade.tachiyomi.ui.reader.ReaderActivity
 import eu.kanade.tachiyomi.ui.recent.history.HistoryController
 import eu.kanade.tachiyomi.ui.recent.updates.UpdatesController
 import eu.kanade.tachiyomi.ui.webview.WebViewActivity
-import eu.kanade.tachiyomi.util.chapter.NoChaptersException
 import eu.kanade.tachiyomi.util.hasCustomCover
 import eu.kanade.tachiyomi.util.lang.launchIO
 import eu.kanade.tachiyomi.util.lang.launchUI
@@ -149,7 +149,6 @@ class MangaController :
 
     private val preferences: PreferencesHelper by injectLazy()
     private val coverCache: CoverCache by injectLazy()
-    private val sourceManager: SourceManager by injectLazy()
 
     private var mangaInfoAdapter: MangaInfoHeaderAdapter? = null
     private var chaptersHeaderAdapter: MangaChaptersHeaderAdapter? = null

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt

@@ -185,7 +185,7 @@ class MangaPresenter(
             return Observable.just(0)
         }
 
-        return db.getTracks(manga).asRxObservable()
+        return db.getTracks(manga.id).asRxObservable()
             .map { tracks ->
                 val loggedServices = trackManager.services.filter { it.isLogged }.map { it.id }
                 tracks.filter { it.sync_id in loggedServices }
@@ -335,7 +335,7 @@ class MangaPresenter(
     fun deleteCustomCover(manga: Manga) {
         Observable
             .fromCallable {
-                coverCache.deleteCustomCover(manga)
+                coverCache.deleteCustomCover(manga.id)
                 manga.updateCoverLastModified(db)
                 coverCache.clearMemoryCache()
             }
@@ -514,7 +514,7 @@ class MangaPresenter(
     }
 
     fun startDownloadingNow(chapter: Chapter) {
-        downloadManager.startDownloadNow(chapter)
+        downloadManager.startDownloadNow(chapter.id)
     }
 
     /**
@@ -720,7 +720,7 @@ class MangaPresenter(
 
     private fun fetchTrackers() {
         trackSubscription?.let { remove(it) }
-        trackSubscription = db.getTracks(manga)
+        trackSubscription = db.getTracks(manga.id)
             .asRxObservable()
             .map { tracks ->
                 loggedServices.map { service ->

app/src/main/java/eu/kanade/tachiyomi/ui/manga/chapter/ChaptersSettingsSheet.kt

@@ -85,9 +85,9 @@ class ChaptersSettingsSheet(
             private val unread = Item.TriStateGroup(R.string.action_filter_unread, this)
             private val bookmarked = Item.TriStateGroup(R.string.action_filter_bookmarked, this)
 
-            override val header = null
+            override val header: Item? = null
             override val items = listOf(downloaded, unread, bookmarked)
-            override val footer = null
+            override val footer: Item? = null
 
             override fun initModels() {
                 if (presenter.forceDownloaded()) {
@@ -138,9 +138,9 @@ class ChaptersSettingsSheet(
             private val chapterNum = Item.MultiSort(R.string.sort_by_number, this)
             private val uploadDate = Item.MultiSort(R.string.sort_by_upload_date, this)
 
-            override val header = null
+            override val header: Item? = null
             override val items = listOf(source, uploadDate, chapterNum)
-            override val footer = null
+            override val footer: Item? = null
 
             override fun initModels() {
                 val sorting = presenter.manga.sorting
@@ -200,9 +200,9 @@ class ChaptersSettingsSheet(
             private val displayTitle = Item.Radio(R.string.show_title, this)
             private val displayChapterNum = Item.Radio(R.string.show_chapter_number, this)
 
-            override val header = null
+            override val header: Item? = null
             override val items = listOf(displayTitle, displayChapterNum)
-            override val footer = null
+            override val footer: Item? = null
 
             override fun initModels() {
                 val mode = presenter.manga.displayMode