Changed scrollToRow: to scrollToIndexPath:

JSQMessagesViewController/Controllers/JSQMessagesViewController.h

@@ -271,9 +271,9 @@
 /** 
  * Scrolls the collection view such that the cell in the given row is completely visible, above the `inputToolbar`.
  *
- * @param row The index of the row that will be visible
+ * @param indexPath The indexPath that will be visible
  * @param animated Pass `YES` if you want to animate scrolling, `NO` if it should be immediate.
  */
-- (void)scrollToRow:(NSInteger)row animated:(BOOL)animated;
+- (void)scrollToIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated;
 
 @end

JSQMessagesViewController/Controllers/JSQMessagesViewController.m

@@ -370,16 +370,17 @@ - (void)scrollToBottomAnimated:(BOOL)animated
         return;
     }
 
-    [self scrollToRow:([self.collectionView numberOfItemsInSection:0] - 1) animated:animated];
+    NSIndexPath *lastCell = [NSIndexPath indexPathForItem:([self.collectionView numberOfItemsInSection:0] - 1) inSection:0];
+    [self scrollToIndexPath:lastCell animated:animated];
 }
 
-- (void)scrollToRow:(NSInteger)row animated:(BOOL)animated
+- (void)scrollToIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated
 {
-    if ([self.collectionView numberOfSections] == 0) {
+    if ([self.collectionView numberOfSections] <= indexPath.section) {
         return;
     }
 
-    NSInteger numberOfItems = [self.collectionView numberOfItemsInSection:0];
+    NSInteger numberOfItems = [self.collectionView numberOfItemsInSection:indexPath.section];
 
     if (numberOfItems == 0) {
         return;
@@ -398,15 +399,14 @@ - (void)scrollToRow:(NSInteger)row animated:(BOOL)animated
     }
 
 
-    row = MAX(MIN(row, numberOfItems - 1), 0);
-    NSIndexPath *indexPath = [NSIndexPath indexPathForItem:row inSection:0];
-    CGSize cellSize = [self.collectionView.collectionViewLayout sizeForItemAtIndexPath:indexPath];
-
-    CGFloat maxHeightForVisibleMessage = CGRectGetHeight(self.collectionView.bounds) - self.collectionView.contentInset.top - CGRectGetHeight(self.inputToolbar.bounds);
+    NSInteger item = MAX(MIN(indexPath.item, numberOfItems - 1), 0);
+    indexPath = [NSIndexPath indexPathForItem:item inSection:0];
 
     //  workaround for really long messages not scrolling
     //  if last message is too long, use scroll position bottom for better appearance, else use top
     //  possibly a UIKit bug, see #480 on GitHub
+    CGSize cellSize = [self.collectionView.collectionViewLayout sizeForItemAtIndexPath:indexPath];
+    CGFloat maxHeightForVisibleMessage = CGRectGetHeight(self.collectionView.bounds) - self.collectionView.contentInset.top - CGRectGetHeight(self.inputToolbar.bounds);
     UICollectionViewScrollPosition scrollPosition = (cellSize.height > maxHeightForVisibleMessage) ? UICollectionViewScrollPositionBottom : UICollectionViewScrollPositionTop;
 
     [self.collectionView scrollToItemAtIndexPath:indexPath