[iOS][MF] Hiden password a11y label

Bug: 878388, 845272
Change-Id: I8f3ee338c35be7d39472b75289106bb563092e92
Reviewed-on: https://chromium-review.googlesource.com/c/1352249
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611127}

ios/chrome/browser/ui/autofill/manual_fill/manual_fill_password_cell.mm

@@ -116,6 +116,8 @@ static const CGFloat NoMultiplier = 1.0;
   [self.usernameButton setTitleColor:UIColor.cr_manualFillTintColor
                             forState:UIControlStateNormal];
   [self.passwordButton setTitle:@"" forState:UIControlStateNormal];
+  self.passwordButton.accessibilityLabel = nil;
+  self.passwordButton.hidden = NO;
   self.manualFillCredential = nil;
 }
 
@@ -176,6 +178,8 @@ static const CGFloat NoMultiplier = 1.0;
 
   if (credential.password.length) {
     [self.passwordButton setTitle:@"••••••••" forState:UIControlStateNormal];
+    self.passwordButton.accessibilityLabel =
+        l10n_util::GetNSString(IDS_IOS_SETTINGS_PASSWORD_HIDDEN_LABEL);
     [verticalLeadViews addObject:self.passwordButton];
     self.passwordButton.hidden = NO;
   } else {