Remove RL VC delayed update on editing.

This does not work well with multiwindow.

Bug: 1106759
Change-Id: Idc2140577d9616babc82b0100ae544641a241ec6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2309701
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791159}

ios/chrome/browser/ui/reading_list/reading_list_table_view_controller.mm

@@ -74,8 +74,6 @@ ReadingListSelectionState GetSelectionStateForSelectedCounts(
 @property(nonatomic, readonly)
     TableViewModel<TableViewItem<ReadingListListItem>*>* tableViewModel;
 
-// Whether the data source has been modified while in editing mode.
-@property(nonatomic, assign) BOOL dataSourceModifiedWhileEditing;
 // The toolbar button manager.
 @property(nonatomic, strong) ReadingListToolbarButtonManager* toolbarManager;
 // The number of read and unread cells that are currently selected.
@@ -102,7 +100,6 @@ ReadingListSelectionState GetSelectionStateForSelectedCounts(
 @synthesize dataSource = _dataSource;
 @synthesize browser = _browser;
 @dynamic tableViewModel;
-@synthesize dataSourceModifiedWhileEditing = _dataSourceModifiedWhileEditing;
 @synthesize toolbarManager = _toolbarManager;
 @synthesize selectedUnreadItemCount = _selectedUnreadItemCount;
 @synthesize selectedReadItemCount = _selectedReadItemCount;
@@ -330,7 +327,6 @@ ReadingListSelectionState GetSelectionStateForSelectedCounts(
 
 - (void)loadModel {
   [super loadModel];
-  self.dataSourceModifiedWhileEditing = NO;
 
   if (self.dataSource.hasElements) {
     [self loadItems];
@@ -350,13 +346,7 @@ ReadingListSelectionState GetSelectionStateForSelectedCounts(
 }
 
 - (void)dataSourceChanged {
-  // If we are editing and monitoring the model updates, set a flag to reload
-  // the data at the end of the editing.
-  if (self.editing) {
-    self.dataSourceModifiedWhileEditing = YES;
-  } else {
   [self reloadData];
-  }
 }
 
 - (NSArray<id<ReadingListListItem>>*)readItems {
@@ -887,9 +877,6 @@ ReadingListSelectionState GetSelectionStateForSelectedCounts(
 
 // Cleanup function called in the completion block of editing operations.
 - (void)batchEditDidFinish {
-  // Reload the items if the datasource was modified during the edit.
-  if (self.dataSourceModifiedWhileEditing)
-    [self reloadData];
   // Remove any newly emptied sections.
   [self removeEmptySections];
 }