[iOS][Password-Breach] Add subtitle to the toggle

Updates the detail text of the switch based on the logged in status
and the preference value.

Bug: 986322
Change-Id: I11f346f003e756c4ab55e75992c7fdf16f1d7492
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1852090Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705076}

ios/chrome/app/strings/ios_strings.grd

@@ -1346,7 +1346,16 @@ Handoff must also be enabled in the General section of Settings, and your device
         Save Passwords
       </message>
       <message name="IDS_IOS_LEAK_CHECK_SWITCH" desc="Title for the switch toggling whether Chrome should check that entered credentials have been part of a leak.">
-       Check password safety
+        Check password safety
+      </message>
+      <message name="IDS_IOS_LEAK_CHECK_SIGNED_IN_DESC" desc="Text that describes the 'Password Leak Detection' functionality to signed-in users.">
+        Warns you if a password you use was part of a data breach.
+      </message>
+      <message name="IDS_IOS_LEAK_CHECK_SIGNED_OUT_DISABLED_DESC" desc="Text that describes the 'Password Leak Detection' functionality to signed-out users who have disabled the feature.">
+        Google can check if your passwords were part of a data breach.
+      </message>
+      <message name="IDS_IOS_LEAK_CHECK_SIGNED_OUT_ENABLED_DESC" desc="Text that describes the 'Password Leak Detection' functionality to signed-out users who have not disabled the feature.">
+        Google can check if your passwords were part of a data breach. This will be turned on when you sign in with your Google Account.
       </message>
       <message name="IDS_IOS_PASSWORDS" desc="Title for the view in Settings for managing saved passwords. [Length: 15em] [iOS only]">
         Passwords

ios/chrome/browser/ui/settings/password/passwords_table_view_controller.mm

@@ -369,6 +369,7 @@ std::vector<std::unique_ptr<autofill::PasswordForm>> CopyOf(
     if (base::FeatureList::IsEnabled(
             password_manager::features::kLeakDetection)) {
       leakCheckItem_ = [self leakCheckItem];
+      [self updateDetailTextLeakCheckItem];
       [model addItem:leakCheckItem_
           toSectionWithIdentifier:SectionIdentifierSavePasswordsSwitch];
     }
@@ -532,6 +533,7 @@ std::vector<std::unique_ptr<autofill::PasswordForm>> CopyOf(
     if ([self.tableViewModel
             hasItemForItemType:ItemTypePasswordLeakCheckSwitch
              sectionIdentifier:SectionIdentifierSavePasswordsSwitch]) {
+      [self updateDetailTextLeakCheckItem];
       [self reconfigureCellsForItems:@[ leakCheckItem_ ]];
     }
   } else {
@@ -555,6 +557,8 @@ std::vector<std::unique_ptr<autofill::PasswordForm>> CopyOf(
 
   // Update the item.
   leakCheckItem_.on = [passwordLeakCheckEnabled_ value];
+  [self updateDetailTextLeakCheckItem];
+  [self reconfigureCellsForItems:@[ leakCheckItem_ ]];
 }
 
 #pragma mark - SavePasswordsConsumerDelegate
@@ -1258,6 +1262,7 @@ std::vector<std::unique_ptr<autofill::PasswordForm>> CopyOf(
   AuthenticationService* authService =
       AuthenticationServiceFactory::GetForBrowserState(browserState_);
   [leakCheckItem_ setEnabled:enabled && authService->IsAuthenticated()];
+  [self updateDetailTextLeakCheckItem];
   [self reconfigureCellsForItems:@[ leakCheckItem_ ]];
 }
 
@@ -1273,6 +1278,29 @@ std::vector<std::unique_ptr<autofill::PasswordForm>> CopyOf(
   }
 }
 
+// Updates the detail text of the leak check item based on the state.
+- (void)updateDetailTextLeakCheckItem {
+  if (!leakCheckItem_) {
+    return;
+  }
+  if (self.editing) {
+    // When editing keep the current detail text.
+    return;
+  }
+  if (leakCheckItem_.enabled) {
+    leakCheckItem_.detailText =
+        l10n_util::GetNSString(IDS_IOS_LEAK_CHECK_SIGNED_IN_DESC);
+    return;
+  }
+  if (leakCheckItem_.on) {
+    leakCheckItem_.detailText =
+        l10n_util::GetNSString(IDS_IOS_LEAK_CHECK_SIGNED_OUT_ENABLED_DESC);
+    return;
+  }
+  leakCheckItem_.detailText =
+      l10n_util::GetNSString(IDS_IOS_LEAK_CHECK_SIGNED_OUT_DISABLED_DESC);
+}
+
 #pragma mark - Testing
 
 - (void)setReauthenticationModuleForExporter: