[iOS][Getaway] Improve blocking UI.

Improves blocking UI in the following ways:
1. Fix handling of large fonts
2. Adjust font size when it's changed in settings
3. Add pointer support
4. Rounded corners are now round irrespectfully of the font size

For this, the authenticate button gets its title as a subview label,
and both buttons are width-constrained to fit.

Bug: 1164922
Change-Id: Ib807ca40e544ec3bc016753b8cfe1501c69c61cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2640439
Auto-Submit: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Sebastien Lalancette <seblalancette@chromium.org>
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845661}

ios/chrome/browser/ui/incognito_reauth/incognito_reauth_view.mm

@@ -22,6 +22,12 @@ const CGFloat kButtonPaddingH = 38.0f;
 const CGFloat kVerticalContentPadding = 70.0f;
 }  // namespace
 
+@interface IncognitoReauthView ()
+// The background view for the authenticate button.
+// Has to be separate from the button because it's a blur view (on iOS 13+).
+@property(nonatomic, weak) UIView* authenticateButtonBackgroundView;
+@end
+
 @implementation IncognitoReauthView
 
 - (instancetype)init {
@@ -53,18 +59,6 @@ const CGFloat kVerticalContentPadding = 70.0f;
                        constant:kVerticalContentPadding]
         .active = YES;
 
-    NSString* unlockButtonTitle = l10n_util::GetNSStringF(
-        IDS_IOS_INCOGNITO_REAUTH_UNLOCK_BUTTON,
-        base::SysNSStringToUTF16(biometricAuthenticationTypeString()));
-    _authenticateButton =
-        [IncognitoReauthView newRoundButtonWithBlurEffect:blurEffect];
-
-    [_authenticateButton setTitle:unlockButtonTitle
-                         forState:UIControlStateNormal];
-    _authenticateButton.accessibilityLabel = l10n_util::GetNSStringF(
-        IDS_IOS_INCOGNITO_REAUTH_UNLOCK_BUTTON_VOICEOVER_LABEL,
-        base::SysNSStringToUTF16(biometricAuthenticationTypeString()));
-
     _tabSwitcherButton = [[UIButton alloc] init];
     _tabSwitcherButton.translatesAutoresizingMaskIntoConstraints = NO;
     [_tabSwitcherButton setTitleColor:[UIColor whiteColor]
@@ -74,55 +68,120 @@ const CGFloat kVerticalContentPadding = 70.0f;
                         forState:UIControlStateNormal];
     _tabSwitcherButton.titleLabel.font =
         [UIFont preferredFontForTextStyle:UIFontTextStyleTitle2];
+    _tabSwitcherButton.titleLabel.adjustsFontSizeToFitWidth = YES;
+    _tabSwitcherButton.titleLabel.adjustsFontForContentSizeCategory = YES;
 
-    [blurBackgroundView.contentView addSubview:_authenticateButton];
-    AddSameCenterConstraints(blurBackgroundView, _authenticateButton);
+#if defined(__IPHONE_13_4)
+    if (@available(iOS 13.4, *)) {
+      _tabSwitcherButton.pointerInteractionEnabled = YES;
+    }
+#endif  // defined(__IPHONE_13_4)
+
+    UIView* authButtonContainer =
+        [self buildAuthenticateButtonWithBlurEffect:blurEffect];
+    [blurBackgroundView.contentView addSubview:authButtonContainer];
+    AddSameCenterConstraints(blurBackgroundView, authButtonContainer);
+    _authenticateButtonBackgroundView = authButtonContainer;
 
     [blurBackgroundView.contentView addSubview:_tabSwitcherButton];
     AddSameCenterXConstraint(_tabSwitcherButton, blurBackgroundView);
+
+    [NSLayoutConstraint activateConstraints:@[
       [_tabSwitcherButton.topAnchor
           constraintEqualToAnchor:blurBackgroundView.safeAreaLayoutGuide
                                       .bottomAnchor
-                       constant:-kVerticalContentPadding]
-        .active = YES;
+                         constant:-kVerticalContentPadding],
+      [_authenticateButton.widthAnchor
+          constraintLessThanOrEqualToAnchor:self.widthAnchor
+                                   constant:-2 * kButtonPaddingH],
+      [_tabSwitcherButton.widthAnchor
+          constraintLessThanOrEqualToAnchor:self.widthAnchor
+                                   constant:-2 * kButtonPaddingH],
+    ]];
+
+    [self setNeedsLayout];
+    [self layoutIfNeeded];
   }
 
   return self;
 }
 
-+ (UIButton*)newRoundButtonWithBlurEffect:(UIBlurEffect*)blurEffect {
-  UIButton* button = [[UIButton alloc] init];
-  button.backgroundColor = [UIColor clearColor];
-  button.titleLabel.font =
-      [UIFont preferredFontForTextStyle:UIFontTextStyleTitle2];
-  button.contentEdgeInsets = UIEdgeInsetsMake(kButtonPaddingV, kButtonPaddingH,
-                                              kButtonPaddingV, kButtonPaddingH);
-  [button
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  self.authenticateButtonBackgroundView.layer.cornerRadius =
+      self.authenticateButtonBackgroundView.frame.size.height / 2;
+}
+
+- (void)traitCollectionDidChange:(UITraitCollection*)previousTraitCollection {
+  [super traitCollectionDidChange:previousTraitCollection];
+  [self setNeedsLayout];
+  [self layoutIfNeeded];
+}
+
+// Creates _authenticateButton.
+// Returns a "decoration" pill-shaped view containing _authenticateButton.
+- (UIView*)buildAuthenticateButtonWithBlurEffect:(UIBlurEffect*)blurEffect {
+  DCHECK(!_authenticateButton);
+
+  // Use a UILabel for the button label, because the built-in UIButton's
+  // |titleLabel| does not correctly resize for multiline labels.
+  UILabel* titleLabel = [[UILabel alloc] init];
+  titleLabel.numberOfLines = 0;
+  titleLabel.textColor = [UIColor whiteColor];
+  titleLabel.textAlignment = NSTextAlignmentCenter;
+  titleLabel.adjustsFontForContentSizeCategory = YES;
+  titleLabel.font = [UIFont preferredFontForTextStyle:UIFontTextStyleTitle2];
+  titleLabel.text = l10n_util::GetNSStringF(
+      IDS_IOS_INCOGNITO_REAUTH_UNLOCK_BUTTON,
+      base::SysNSStringToUTF16(biometricAuthenticationTypeString()));
+  [titleLabel
       setContentCompressionResistancePriority:UILayoutPriorityRequired
                                       forAxis:UILayoutConstraintAxisHorizontal];
-  [button
+  [titleLabel
       setContentCompressionResistancePriority:UILayoutPriorityRequired
                                       forAxis:UILayoutConstraintAxisVertical];
+  titleLabel.translatesAutoresizingMaskIntoConstraints = NO;
+  // Disable a11y; below the UIButton will get a correct label.
+  titleLabel.accessibilityLabel = nil;
+
+  UIButton* button = [[UIButton alloc] init];
+  button.backgroundColor = [UIColor clearColor];
+
+  button.accessibilityLabel = l10n_util::GetNSStringF(
+      IDS_IOS_INCOGNITO_REAUTH_UNLOCK_BUTTON_VOICEOVER_LABEL,
+      base::SysNSStringToUTF16(biometricAuthenticationTypeString()));
   button.translatesAutoresizingMaskIntoConstraints = NO;
-  [button sizeToFit];
+  [button addSubview:titleLabel];
+  AddSameConstraintsWithInsets(
+
+      button, titleLabel,
+      ChromeDirectionalEdgeInsetsMake(-kButtonPaddingV, -kButtonPaddingH,
+                                      -kButtonPaddingV, -kButtonPaddingH));
+
+#if defined(__IPHONE_13_4)
+  if (@available(iOS 13.4, *)) {
+    button.pointerInteractionEnabled = YES;
+  }
+#endif  // defined(__IPHONE_13_4)
 
   UIView* backgroundView = nil;
   if (@available(iOS 13, *)) {
-    backgroundView = [[UIVisualEffectView alloc]
+    UIVisualEffectView* effectView = [[UIVisualEffectView alloc]
         initWithEffect:[UIVibrancyEffect
                            effectForBlurEffect:blurEffect
                                          style:UIVibrancyEffectStyleFill]];
+    [effectView.contentView addSubview:button];
+    backgroundView = effectView;
   } else {
     backgroundView = [[UIView alloc] init];
+    [backgroundView addSubview:button];
   }
   backgroundView.backgroundColor = [UIColor colorWithWhite:1 alpha:0.2];
-  backgroundView.layer.cornerRadius = button.frame.size.height / 2;
   backgroundView.translatesAutoresizingMaskIntoConstraints = NO;
-  backgroundView.userInteractionEnabled = NO;
-  [button addSubview:backgroundView];
-  AddSameConstraints(backgroundView, button);
 
-  return button;
+  AddSameConstraints(backgroundView, button);
+  _authenticateButton = button;
+  return backgroundView;
 }
 
 #pragma mark - voiceover