Workaround for iOS 12

This CL changes the layout of the tabCountLabel in the TabGrid button
to position it with autolayout, to prevent the app from freezing when
rotating.

Bug: none
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I104b6c17c336e27301e2c991f0524f2fbf9062c9
Reviewed-on: https://chromium-review.googlesource.com/1136446Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574898}

ios/chrome/browser/ui/toolbar/buttons/toolbar_tab_grid_button.mm

@@ -15,7 +15,7 @@
 #endif
 
 namespace {
-const CGFloat kLabelMargin = 7;
+const CGFloat kLabelSize = 14;
 }  // namespace
 
 @interface ToolbarTabGridButton ()
@@ -70,8 +70,12 @@ const CGFloat kLabelMargin = 7;
     _tabCountLabel = [[UILabel alloc] init];
     [self addSubview:_tabCountLabel];
 
-    CGRect imageFrame = self.imageView.frame;
-    _tabCountLabel.frame = CGRectInset(imageFrame, kLabelMargin, kLabelMargin);
+    _tabCountLabel.translatesAutoresizingMaskIntoConstraints = NO;
+    [NSLayoutConstraint activateConstraints:@[
+      [_tabCountLabel.widthAnchor constraintEqualToConstant:kLabelSize],
+      [_tabCountLabel.heightAnchor constraintEqualToConstant:kLabelSize],
+    ]];
+    AddSameCenterConstraints(self, _tabCountLabel);
 
     _tabCountLabel.font = [UIFont systemFontOfSize:kTabGridButtonFontSize
                                             weight:UIFontWeightBold];
@@ -84,14 +88,4 @@ const CGFloat kLabelMargin = 7;
   return _tabCountLabel;
 }
 
-- (void)layoutSubviews {
-  [super layoutSubviews];
-
-  if (!_tabCountLabel)
-    return;
-  CGRect imageFrame = self.imageView.frame;
-  self.tabCountLabel.frame =
-      CGRectInset(imageFrame, kLabelMargin, kLabelMargin);
-}
-
 @end