[iOS] Fix TabGrid toolbar button constraints

This CL removes the autolayout constraints on the TabGrid button in the
toolbar and instead positions it using frames.

Bug: 862576
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I5eda2cc58ee38228e40870f723315bc91ac6953f
Reviewed-on: https://chromium-review.googlesource.com/1133167Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574153}

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

@@ -66,16 +66,11 @@ const CGFloat kLabelMargin = 7;
 - (UILabel*)tabCountLabel {
   if (!_tabCountLabel) {
     _tabCountLabel = [[UILabel alloc] init];
-    _tabCountLabel.translatesAutoresizingMaskIntoConstraints = NO;
-    [_tabCountLabel setContentHuggingPriority:UILayoutPriorityDefaultLow
-                                      forAxis:UILayoutConstraintAxisHorizontal];
     [self addSubview:_tabCountLabel];
-    AddSameConstraintsToSidesWithInsets(
-        _tabCountLabel, self.imageView,
-        LayoutSides::kTop | LayoutSides::kBottom | LayoutSides::kLeading |
-            LayoutSides::kTrailing,
-        ChromeDirectionalEdgeInsetsMake(kLabelMargin, kLabelMargin,
-                                        kLabelMargin, kLabelMargin));
+
+    CGRect imageFrame = self.imageView.frame;
+    _tabCountLabel.frame = CGRectInset(imageFrame, kLabelMargin, kLabelMargin);
+
     _tabCountLabel.font = [UIFont systemFontOfSize:kTabGridButtonFontSize
                                             weight:UIFontWeightBold];
     _tabCountLabel.adjustsFontSizeToFitWidth = YES;
@@ -87,4 +82,14 @@ 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