* ImageUtil.chooseBackground: Use built-in decoder * PagerPageHolder: Move chooseBackground call to IO thread Also move stuffs and reuse image stream as bytes (cherry picked from commit 11a8046c5fa00a6abbaf387ab5c75a9a294a01b8) # Conflicts: # app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/pager/PagerPageHolder.kt