[iOS][DarkMode] Tint the blue checkmark

Bug: 976640
Change-Id: I800958a1e853e1c4c23cc76d178c8a64b6563e1f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1698369
Auto-Submit: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676851}

ios/chrome/browser/ui/first_run/welcome_to_chrome_view.mm

@@ -293,8 +293,10 @@ const char kPrivacyNoticeUrl[] = "internal://privacy-notice";
         setAccessibilityValue:l10n_util::GetNSString(IDS_IOS_SETTING_OFF)];
     [_checkBoxButton setImage:[UIImage imageNamed:kCheckBoxImageName]
                      forState:UIControlStateNormal];
-    [_checkBoxButton setImage:[UIImage imageNamed:kCheckBoxCheckedImageName]
-                     forState:UIControlStateSelected];
+    UIImage* selectedImage = [[UIImage imageNamed:kCheckBoxCheckedImageName]
+        imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
+    [_checkBoxButton setImage:selectedImage forState:UIControlStateSelected];
+    _checkBoxButton.tintColor = [UIColor colorNamed:kTintColor];
   }
   return _checkBoxButton;
 }