Revert "Add workaround for bug in iOS 11.1 beta around hit area of custom back buttons."

This reverts commit 7c82f6d448.

This wasn't helping our crash rate, and on my device, as of iOS11.1B2,
the button is easily tappable, not detectably different from prior iOS
releases.

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -1328,29 +1328,27 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
     (OWSDisappearingMessagesConfiguration *)disappearingMessagesConfiguration
 {
     UIBarButtonItem *backItem = [self createOWSBackButton];
-    if (backItem.customView) {
-        // This method gets called multiple times, so it's important we re-layout the unread badge
-        // with respect to the new backItem.
-        [backItem.customView addSubview:_backButtonUnreadCountView];
-        // TODO: The back button assets are assymetrical.  There are strong reasons
-        // to use spacing in the assets to manipulate the size and positioning of
-        // bar button items, but it means we'll probably need separate RTL and LTR
-        // flavors of these assets.
-        [_backButtonUnreadCountView autoPinEdgeToSuperviewEdge:ALEdgeTop withInset:-6];
-        [_backButtonUnreadCountView autoPinLeadingToSuperviewWithMargin:1];
-        [_backButtonUnreadCountView autoSetDimension:ALDimensionHeight toSize:self.unreadCountViewDiameter];
-        // We set a min width, but we will also pin to our subview label, so we can grow to accommodate multiple digits.
-        [_backButtonUnreadCountView autoSetDimension:ALDimensionWidth
-                                              toSize:self.unreadCountViewDiameter
-                                            relation:NSLayoutRelationGreaterThanOrEqual];
-
-        [_backButtonUnreadCountView addSubview:_backButtonUnreadCountLabel];
-        [_backButtonUnreadCountLabel autoPinWidthToSuperviewWithMargin:4];
-        [_backButtonUnreadCountLabel autoPinHeightToSuperview];
-
-        // Initialize newly created unread count badge to accurately reflect the current unread count.
-        [self updateBackButtonUnreadCount];
-    }
+    // This method gets called multiple times, so it's important we re-layout the unread badge
+    // with respect to the new backItem.
+    [backItem.customView addSubview:_backButtonUnreadCountView];
+    // TODO: The back button assets are assymetrical.  There are strong reasons
+    // to use spacing in the assets to manipulate the size and positioning of
+    // bar button items, but it means we'll probably need separate RTL and LTR
+    // flavors of these assets.
+    [_backButtonUnreadCountView autoPinEdgeToSuperviewEdge:ALEdgeTop withInset:-6];
+    [_backButtonUnreadCountView autoPinLeadingToSuperviewWithMargin:1];
+    [_backButtonUnreadCountView autoSetDimension:ALDimensionHeight toSize:self.unreadCountViewDiameter];
+    // We set a min width, but we will also pin to our subview label, so we can grow to accommodate multiple digits.
+    [_backButtonUnreadCountView autoSetDimension:ALDimensionWidth
+                                          toSize:self.unreadCountViewDiameter
+                                        relation:NSLayoutRelationGreaterThanOrEqual];
+
+    [_backButtonUnreadCountView addSubview:_backButtonUnreadCountLabel];
+    [_backButtonUnreadCountLabel autoPinWidthToSuperviewWithMargin:4];
+    [_backButtonUnreadCountLabel autoPinHeightToSuperview];
+
+    // Initialize newly created unread count badge to accurately reflect the current unread count.
+    [self updateBackButtonUnreadCount];
 
     self.navigationItem.leftBarButtonItem = backItem;
 

Signal/src/util/UIViewController+OWS.m

@@ -53,22 +53,6 @@ NS_ASSUME_NONNULL_BEGIN
         = CGRectMake(0, 0, backImage.size.width + kExtraRightPadding, backImage.size.height + kExtraHeightPadding);
     backButton.frame = buttonFrame;
 
-    if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(11, 1)) {
-        // In iOS 11.1 beta, the hot area of custom bar button items is _only_
-        // the bounds of the custom view, making them very hard to hit.
-        //
-        // TODO: Remove this hack if the bug is fixed in iOS 11.1 by the time
-        //       it goes to production (or in a later release),
-        //       since it has two negative side effects: 1) the layout of the
-        //       back button isn't consistent with the iOS default back buttons
-        //       2) we can't add the unread count badge to the back button
-        //       with this hack.
-        return [[UIBarButtonItem alloc] initWithImage:backImage
-                                                style:UIBarButtonItemStylePlain
-                                               target:target
-                                               action:selector];
-    }
-
     UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
     backItem.width = buttonFrame.size.width;