Reload the ReadingListCollection only if changes occurred

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

Index: ios/chrome/browser/ui/reading_list/reading_list_collection_view_item.mm
diff --git a/ios/chrome/browser/ui/reading_list/reading_list_collection_view_item.mm b/ios/chrome/browser/ui/reading_list/reading_list_collection_view_item.mm
index c90b5e365f205f79d71d220f15986a6847005032..8c5a1a31998e105062be3a96d226defdda6a786a 100644
--- a/ios/chrome/browser/ui/reading_list/reading_list_collection_view_item.mm
+++ b/ios/chrome/browser/ui/reading_list/reading_list_collection_view_item.mm
@@ -47,7 +47,6 @@ const CGFloat kDistillationIndicatorSize = 18;
 
 @interface ReadingListCollectionViewItem ()<ReadingListCellDelegate> {
   GURL _url;
-  ReadingListEntry::DistillationState _distillationState;
 }
 // Attributes provider used to retrieve favicons.
 @property(nonatomic, strong)
@@ -66,6 +65,7 @@ const CGFloat kDistillationIndicatorSize = 18;
 @synthesize detailText = _detailText;
 @synthesize url = _url;
 @synthesize displayedCell = _displayedCell;
+@synthesize distillationState = _distillationState;
 
 - (instancetype)initWithType:(NSInteger)type
           attributesProvider:(FaviconAttributesProvider*)provider
@@ -96,6 +96,14 @@ const CGFloat kDistillationIndicatorSize = 18;
   return self;
 }
 
+#pragma mark - property
+
+- (void)setDistillationState:
+    (ReadingListEntry::DistillationState)distillationState {
+  self.displayedCell.distillationState = distillationState;
+  _distillationState = distillationState;
+}
+
 #pragma mark - CollectionViewTextItem
 
 - (void)configureCell:(ReadingListCell*)cell {
@@ -128,6 +136,18 @@ const CGFloat kDistillationIndicatorSize = 18;
                                     self.text, self.detailText];
 }
 
+- (BOOL)isEqual:(id)other {
+  if (other == self)
+    return YES;
+  if (!other || ![other isKindOfClass:[self class]])
+    return NO;
+  ReadingListCollectionViewItem* otherItem =
+      static_cast<ReadingListCollectionViewItem*>(other);
+  return [self.text isEqualToString:otherItem.text] &&
+         [self.detailText isEqualToString:otherItem.detailText] &&
+         self.distillationState == otherItem.distillationState;
+}
+
 @end
 
 #pragma mark - ReadingListCell
@@ -220,7 +240,7 @@ const CGFloat kDistillationIndicatorSize = 18;
   }
 }
 
-#pragma mark UICollectionViewCell
+#pragma mark - UICollectionViewCell
 
 - (void)prepareForReuse {
   [self.delegate readingListCellWillPrepareForReload:self];