refactor: remove redundant fragment tracking and padding property for cleaner viewpager2 integration

Author: erkasraim

readium/navigator/src/main/java/org/readium/r2/navigator/pager/R2EpubPageFragment.kt

@@ -387,13 +387,6 @@ internal class R2EpubPageFragment : Fragment() {
     }
 
     internal val paddingTop: Int get() = containerView.paddingTop
-    internal val paddingBottom: Int get() = containerView.paddingBottom
-
-    private val isCurrentResource: Boolean get() {
-        val epubNavigator = navigator ?: return false
-        val currentFragment = (epubNavigator.resourcePager.adapter as? R2PagerAdapter)?.getCurrentFragment() as? R2EpubPageFragment ?: return false
-        return tag == currentFragment.tag
-    }
 
     private fun onLoadPage() {
         if (!isLoading) return

readium/navigator/src/main/java/org/readium/r2/navigator/pager/R2PagerAdapter.kt

@@ -40,14 +40,6 @@ internal class R2PagerAdapter internal constructor(
         data class Cbz(val link: Link) : PageResource()
     }
 
-    private var currentFragment: Fragment? = null
-    private var previousFragment: Fragment? = null
-    private var nextFragment: Fragment? = null
-
-    fun getCurrentFragment(): Fragment? = currentFragment
-    fun getPreviousFragment(): Fragment? = previousFragment
-    fun getNextFragment(): Fragment? = nextFragment
-
     internal fun getResource(position: Int): PageResource? = resources.getOrNull(position)
 
     override fun getItem(position: Int): Fragment {