[ios pointer support] signin_promo_view

iOS 13.4 introduces new APIs for mouse cursor support on iPad.

Buttons should react to pointer hover. This CL enables the default
hover effect on signin_promo_view buttons.

signed out. Open bookmarks. Check hover pointer effect on
"Sign into Chrome" and close buttons.

Test: iPad-only. Enable pointer support flag. Account should be
Bug: 1073961
Change-Id: Iece3506e0c98142383d9fa6814f4956c4af43136
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2166414Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Commit-Queue: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762783}

ios/chrome/browser/ui/authentication/cells/BUILD.gn

@@ -23,6 +23,7 @@ source_set("cells") {
     "//build:branding_buildflags",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser",
+    "//ios/chrome/browser/ui:feature_flags",
     "//ios/chrome/browser/ui/collection_view/cells",
     "//ios/chrome/browser/ui/colors",
     "//ios/chrome/browser/ui/commands",

ios/chrome/browser/ui/authentication/cells/signin_promo_view.mm

@@ -4,6 +4,7 @@
 
 #import "ios/chrome/browser/ui/authentication/cells/signin_promo_view.h"
 
+#include "base/feature_list.h"
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "build/branding_buildflags.h"
@@ -11,6 +12,7 @@
 #import "ios/chrome/browser/ui/authentication/cells/signin_promo_view_constants.h"
 #import "ios/chrome/browser/ui/authentication/cells/signin_promo_view_delegate.h"
 #import "ios/chrome/browser/ui/colors/MDCPalette+CrAdditions.h"
+#include "ios/chrome/browser/ui/ui_feature_flags.h"
 #import "ios/chrome/browser/ui/util/uikit_ui_util.h"
 #import "ios/chrome/common/ui/colors/UIColor+cr_semantic_colors.h"
 #import "ios/chrome/common/ui/colors/semantic_color_names.h"
@@ -110,6 +112,13 @@ const CGFloat kImageViewWidthHeight = 32;
                        action:@selector(onPrimaryButtonAction:)
              forControlEvents:UIControlEventTouchUpInside];
     _primaryButton.contentEdgeInsets = primaryButtonInsets;
+#if defined(__IPHONE_13_4)
+    if (@available(iOS 13.4, *)) {
+      if (base::FeatureList::IsEnabled(kPointerSupport)) {
+        _primaryButton.pointerInteractionEnabled = YES;
+      }
+    }
+#endif  // defined(__IPHONE_13_4)
 
     // Create and setup seconday button.
     UIButton* secondaryButton;
@@ -125,6 +134,13 @@ const CGFloat kImageViewWidthHeight = 32;
     [_secondaryButton addTarget:self
                          action:@selector(onSecondaryButtonAction:)
                forControlEvents:UIControlEventTouchUpInside];
+#if defined(__IPHONE_13_4)
+    if (@available(iOS 13.4, *)) {
+      if (base::FeatureList::IsEnabled(kPointerSupport)) {
+        _secondaryButton.pointerInteractionEnabled = YES;
+      }
+    }
+#endif  // defined(__IPHONE_13_4)
 
     // Vertical stackView containing all previous view.
     UIStackView* verticalStackView =
@@ -147,6 +163,13 @@ const CGFloat kImageViewWidthHeight = 32;
     [_closeButton setImage:[UIImage imageNamed:@"signin_promo_close_gray"]
                   forState:UIControlStateNormal];
     _closeButton.hidden = YES;
+#if defined(__IPHONE_13_4)
+    if (@available(iOS 13.4, *)) {
+      if (base::FeatureList::IsEnabled(kPointerSupport)) {
+        _closeButton.pointerInteractionEnabled = YES;
+      }
+    }
+#endif  // defined(__IPHONE_13_4)
     [self addSubview:_closeButton];
 
     [NSLayoutConstraint activateConstraints:@[