Extract message bubble view.

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -2299,14 +2299,6 @@ typedef enum : NSUInteger {
 
 - (void)scrollDownButtonTapped
 {
-#ifdef DEBUG
-    CGPoint contentOffset = self.collectionView.contentOffset;
-    contentOffset.y += self.collectionView.height
-        - (self.collectionView.contentInset.top + self.collectionView.contentInset.bottom);
-    [self.collectionView setContentOffset:contentOffset animated:NO];
-    return;
-#endif
-
     NSIndexPath *indexPathOfUnreadMessagesIndicator = [self indexPathOfUnreadMessagesIndicator];
     if (indexPathOfUnreadMessagesIndicator != nil) {
         NSInteger unreadRow = indexPathOfUnreadMessagesIndicator.row;

Signal/src/ViewControllers/HomeViewController.m

@@ -284,15 +284,6 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
     }
 
     [self updateBarButtonItems];
-
-    dispatch_async(dispatch_get_main_queue(), ^{
-        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
-        TSThread *thread = [self threadForIndexPath:indexPath];
-        if (!thread) {
-            return;
-        }
-        [self presentThread:thread keyboardOnViewAppearing:NO callOnViewAppearing:NO];
-    });
 }
 
 - (void)viewDidAppear:(BOOL)animated