Add close-all-tabs-confirmation flag

This flag adds a confirmation dialog when the user chooses the option to
close all tabs at once. Consequently, the Undo button is no longer
shown.

Fixed: 1410767
Change-Id: I681fdeaee4340980ad5e58ea43f555bcd1e50753
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4197605
Commit-Queue: Louis Romero <[email protected]>
Reviewed-by: Aliona Dangla <[email protected]>
Auto-Submit: Louis Romero <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1097948}
diff --git a/ios/chrome/browser/flags/about_flags.mm b/ios/chrome/browser/flags/about_flags.mm
index 70f43905..1057fa0 100644
--- a/ios/chrome/browser/flags/about_flags.mm
+++ b/ios/chrome/browser/flags/about_flags.mm
@@ -1282,6 +1282,10 @@
      flag_descriptions::kEnableFeedSyntheticCapabilitiesName,
      flag_descriptions::kEnableFeedSyntheticCapabilitiesDescription,
      flags_ui::kOsIos, FEATURE_VALUE_TYPE(kEnableFeedSyntheticCapabilities)},
+    {"close-all-tabs-confirmation",
+     flag_descriptions::kCloseAllTabsConfirmationName,
+     flag_descriptions::kCloseAllTabsConfirmationDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(kCloseAllTabsConfirmation)},
 };
 
 bool SkipConditionalFeatureEntry(const flags_ui::FeatureEntry& entry) {