Closes #24276:

– make comments inside HistoryDataSource capitalized and informative
– remove scroll to first item in swipe-to-refresh
– change adapter initialization
– fixed SitePermissionsExceptionsFragment flickering empty state

app/src/main/java/org/mozilla/fenix/library/history/HistoryDataSource.kt

@@ -14,12 +14,13 @@ class HistoryDataSource(
     private val historyProvider: PagedHistoryProvider
 ) : PagingSource<Int, History>() {
 
-    // having any value but null creates visual glitches in case or swipe to refresh and immediate
-    // scroll down
+    // The refresh key is set to null so that it will always reload the entire list for any data
+    // updates such as pull to refresh, and return the user to the start of the list.
     override fun getRefreshKey(state: PagingState<Int, History>): Int? = null
 
-    // params.key is expected to be null for the initial load or a refresh
     override suspend fun load(params: LoadParams<Int>): LoadResult<Int, History> {
+        // Get the offset of the last loaded page or default to 0 when it is null, on the initial
+        // load or a refresh.
         val offset = params.key ?: 0
         val historyItems = historyProvider.getHistory(offset, params.loadSize).run {
             positionWithOffset(offset)
@@ -29,10 +30,9 @@ class HistoryDataSource(
         } else {
             (offset + historyItems.size) + 1
         }
-        // prevKey is needed in case load would work upwards, so passing null is fine
         return LoadResult.Page(
             data = historyItems,
-            prevKey = null,
+            prevKey = null, // Only paging forward.
             nextKey = nextOffset
         )
     }

app/src/main/java/org/mozilla/fenix/library/history/HistoryView.kt

@@ -65,7 +65,6 @@ class HistoryView(
         binding.swipeRefresh.setColorSchemeColors(primaryTextColor)
         binding.swipeRefresh.setOnRefreshListener {
             interactor.onRequestSync()
-            binding.historyList.scrollToPosition(0)
         }
     }
 

app/src/main/java/org/mozilla/fenix/settings/sitepermissions/SitePermissionsExceptionsFragment.kt

@@ -68,9 +68,12 @@ class SitePermissionsExceptionsFragment :
                 ) {
                     showEmptyListMessage()
                 } else {
-                    hideEmptyListMessage()
+                    if (itemCount != 0) {
+                        hideEmptyListMessage()
+                    }
                 }
             }
+            recyclerView.adapter = this
         }
 
         viewLifecycleOwner.lifecycleScope.launch(Dispatchers.IO) {
@@ -85,8 +88,6 @@ class SitePermissionsExceptionsFragment :
                 adapter.submitData(it)
             }
         }
-
-        recyclerView.adapter = adapter
     }
 
     private fun hideEmptyListMessage() {