[ios] Revert back to a card style for settings.

The card style is now disabled behind a new IsSettingsUIRebootEnabled()
experimental flag.

These changes were inadvertently landed as part of
https://chromium-review.googlesource.com/c/chromium/src/+/1114605.

BUG=805213

Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I7c22b635199810bab3332443e8a9251c073ca245
Reviewed-on: https://chromium-review.googlesource.com/1116919Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570748}

ios/chrome/browser/experimental_flags.h

@@ -72,6 +72,9 @@ bool IsReadingListUIRebootEnabled();
 // Whether the Collections UI Reboot is enabled.
 bool IsCollectionsUIRebootEnabled();
 
+// Whether the Settings UI Reboot is enabled.
+bool IsSettingsUIRebootEnabled();
+
 // Whether the application group sandbox must be cleared before starting.
 // Calling this method will reset the flag to false, so the sandbox is cleared
 // only once.

ios/chrome/browser/experimental_flags.mm

@@ -151,4 +151,8 @@ bool IsCollectionsUIRebootEnabled() {
   return base::FeatureList::IsEnabled(kCollectionsUIReboot);
 }
 
+bool IsSettingsUIRebootEnabled() {
+  return base::FeatureList::IsEnabled(kCollectionsUIReboot);
+}
+
 }  // namespace experimental_flags

ios/chrome/browser/ui/settings/settings_root_collection_view_controller.mm

@@ -8,6 +8,7 @@
 #import "base/mac/foundation_util.h"
 
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#import "ios/chrome/browser/experimental_flags.h"
 #import "ios/chrome/browser/ui/commands/application_commands.h"
 #import "ios/chrome/browser/ui/commands/open_url_command.h"
 #import "ios/chrome/browser/ui/settings/bar_button_activity_indicator.h"
@@ -53,9 +54,15 @@ const CGFloat kActivityIndicatorDimensionIPhone = 56;
       self.collectionViewAccessibilityIdentifier;
 
   // Customize collection view settings.
-  self.collectionView.backgroundColor = [UIColor groupTableViewBackgroundColor];
-  self.styler.cellStyle = MDCCollectionViewCellStyleGrouped;
-  self.styler.separatorInset = UIEdgeInsetsMake(0, 48, 0, 0);
+  if (experimental_flags::IsSettingsUIRebootEnabled()) {
+    self.collectionView.backgroundColor =
+        [UIColor groupTableViewBackgroundColor];
+    self.styler.cellStyle = MDCCollectionViewCellStyleGrouped;
+    self.styler.separatorInset = UIEdgeInsetsMake(0, 48, 0, 0);
+  } else {
+    self.styler.cellStyle = MDCCollectionViewCellStyleCard;
+    self.styler.separatorInset = UIEdgeInsetsMake(0, 16, 0, 16);
+  }
 }
 
 - (void)viewWillAppear:(BOOL)animated {