image: optimize grouping routine

Turns out the image grouping routine runs on the main thread and is
slow enough to cause massive freezing. Attempt to resolve this.

app/src/main/java/org/oxycblt/auxio/image/CoverView.kt

@@ -322,7 +322,11 @@ constructor(context: Context, attrs: AttributeSet? = null, @AttrRes defStyleAttr
      *
      * @param song The [Song] to bind to the view.
      */
-    fun bind(song: Song) = bind(song.album)
+    fun bind(song: Song) =
+        bind(
+            listOf(song),
+            context.getString(R.string.desc_album_cover, song.album.name),
+            R.drawable.ic_album_24)
 
     /**
      * Bind an [Album]'s image to this view.

app/src/main/java/org/oxycblt/auxio/image/extractor/CoverExtractor.kt

@@ -117,13 +117,17 @@ constructor(
      *   by their names. "Representation" is defined by how many [Song]s were found to be linked to
      *   the given [Album] in the given [Song] list.
      */
-    fun computeCoverOrdering(songs: List<Song>) =
-        Sort(Sort.Mode.ByAlbum, Sort.Direction.ASCENDING)
-            .songs(songs)
-            .groupBy { it.album }
-            .entries
-            .sortedByDescending { it.value.size }
-            .map { it.key }
+    fun computeCoverOrdering(songs: List<Song>): List<Album> {
+        if (songs.isEmpty()) return listOf()
+        if (songs.size == 1) return listOf(songs.first().album)
+
+        val sortedMap =
+            sortedMapOf<Album, Int>(Sort.Mode.ByName.getAlbumComparator(Sort.Direction.ASCENDING))
+        for (song in songs) {
+            sortedMap[song.album] = (sortedMap[song.album] ?: 0) + 1
+        }
+        return sortedMap.keys.sortedByDescending { sortedMap[it] }
+    }
 
     private suspend fun openCoverInputStream(album: Album) =
         try {
@@ -205,7 +209,7 @@ constructor(
         withContext(Dispatchers.IO) { context.contentResolver.openInputStream(album.coverUri) }
 
     /** Derived from phonograph: https://github.com/kabouzeid/Phonograph */
-    private suspend fun createMosaic(streams: List<InputStream>, size: Size): FetchResult {
+    private fun createMosaic(streams: List<InputStream>, size: Size): FetchResult {
         // Use whatever size coil gives us to create the mosaic.
         val mosaicSize = AndroidSize(size.width.mosaicSize(), size.height.mosaicSize())
         val mosaicFrameSize =

app/src/main/java/org/oxycblt/auxio/util/ContextUtil.kt

@@ -23,7 +23,6 @@ import android.content.Context
 import android.content.Intent
 import android.content.res.ColorStateList
 import android.content.res.Configuration
-import android.os.Build
 import android.util.TypedValue
 import android.view.LayoutInflater
 import android.widget.Toast