[iOS][Chrome-Guard] Adds a footer to cookies settings

This CL adds a footer to cookies settings, explaining to the user
how to apply the new cookies setting.

Bug: 1063824
Change-Id: Ib683b385115f30f6b46eceb7a30741ca0a0a99d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2248563
Commit-Queue: Ewann Pellé <ewannpv@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779764}

ios/chrome/app/strings/ios_strings.grd

@@ -1224,6 +1224,9 @@ While in incognito, sites can't use cookies to see your browsing activity across
       <message name="IDS_IOS_OPTIONS_PRIVACY_COOKIES_BLOCK_THIRD_PARTY_COOKIES_TITLE" desc="Option title to block third party cookies">
         Block Third-Party Cookies
       </message>
+      <message name="IDS_IOS_OPTIONS_PRIVACY_COOKIES_FOOTER" desc="Footer description explaining how to apply the new cookies setting">
+        Your cookies setting applies to all tabs. To apply a new setting to an open tab, reload the tab.
+      </message>
       <message name="IDS_IOS_OPTIONS_PRIVACY_GOOGLE_SERVICES_FOOTER" desc="Footer to invite the user to open the Sync and Google Services settings.">
         For more settings that relate to privacy, security, and data collection, see <ph name="BEGIN_LINK">BEGIN_LINK</ph>Sync and Google Services<ph name="END_LINK">END_LINK</ph>.
       </message>

ios/chrome/app/strings/ios_strings_grd/IDS_IOS_OPTIONS_PRIVACY_COOKIES_FOOTER.png.sha1

+27898f72ae64a660f82db16f46cbe8aefe7329ab
\ No newline at end of file

ios/chrome/browser/ui/settings/privacy/cookies_view_controller.mm

@@ -10,10 +10,8 @@
 #import "ios/chrome/browser/ui/settings/settings_navigation_controller.h"
 #import "ios/chrome/browser/ui/table_view/cells/table_view_info_button_cell.h"
 #import "ios/chrome/browser/ui/table_view/cells/table_view_info_button_item.h"
-#import "ios/chrome/browser/ui/table_view/cells/table_view_text_header_footer_item.h"
 #import "ios/chrome/browser/ui/table_view/cells/table_view_text_item.h"
 #import "ios/chrome/browser/ui/table_view/cells/table_view_text_link_item.h"
-#import "ios/chrome/browser/ui/table_view/cells/table_view_url_item.h"
 #import "ios/chrome/browser/ui/table_view/chrome_table_view_styler.h"
 #include "ios/chrome/browser/ui/ui_feature_flags.h"
 #import "ios/chrome/common/ui/colors/UIColor+cr_semantic_colors.h"
@@ -33,6 +31,7 @@ typedef NS_ENUM(NSInteger, ItemType) {
   ItemTypeBlockThirdPartyCookiesIncognito,
   ItemTypeBlockThirdPartyCookies,
   ItemTypeBlockAllCookies,
+  ItemTypeCookiesDescriptionFooter,
 };
 
 typedef NS_ENUM(NSInteger, SectionIdentifier) {
@@ -130,6 +129,14 @@ typedef NS_ENUM(NSInteger, SectionIdentifier) {
   blockAllCookies.iconImageName = @"accessory_no_checkmark";
   [self.tableViewModel addItem:blockAllCookies
        toSectionWithIdentifier:SectionIdentifierCookiesContent];
+
+  TableViewTextLinkItem* cookiesDescriptionFooter =
+      [[TableViewTextLinkItem alloc]
+          initWithType:ItemTypeCookiesDescriptionFooter];
+  cookiesDescriptionFooter.text =
+      l10n_util::GetNSString(IDS_IOS_OPTIONS_PRIVACY_COOKIES_FOOTER);
+  [self.tableViewModel addItem:cookiesDescriptionFooter
+       toSectionWithIdentifier:SectionIdentifierCookiesContent];
 }
 
 #pragma mark - Private
@@ -238,6 +245,10 @@ typedef NS_ENUM(NSInteger, SectionIdentifier) {
         cellForRowAtIndexPath:(NSIndexPath*)indexPath {
   UITableViewCell* cell = [super tableView:tableView
                      cellForRowAtIndexPath:indexPath];
+  if ([self.tableViewModel itemTypeForIndexPath:indexPath] ==
+      ItemTypeCookiesDescriptionFooter)
+    return cell;
+
   TableViewInfoButtonCell* managedCell =
       base::mac::ObjCCastStrict<TableViewInfoButtonCell>(cell);
   [managedCell.trailingButton addTarget:self