Change name of NativeTheme::instance() to make it clear it's web only.

chrome/browser/ui/sync/profile_signin_confirmation_helper.cc

Index: chrome/browser/ui/sync/profile_signin_confirmation_helper.cc
diff --git a/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc b/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc
index 7934c49fe7ce109a62de53774e4efafd92ec9065..f27aa0ed73844c4d14d75ca8b43849800b76e5c4 100644
--- a/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc
+++ b/chrome/browser/ui/sync/profile_signin_confirmation_helper.cc
@@ -43,10 +43,10 @@ bool HasBookmarks(Profile* profile) {
 
 namespace ui {
 
-SkColor GetSigninConfirmationPromptBarColor(SkAlpha alpha) {
+SkColor GetSigninConfirmationPromptBarColor(ui::NativeTheme* theme,
+                                            SkAlpha alpha) {
   static const SkColor kBackgroundColor =
-      ui::NativeTheme::instance()->GetSystemColor(
-          ui::NativeTheme::kColorId_DialogBackground);
+      theme->GetSystemColor(ui::NativeTheme::kColorId_DialogBackground);
   return color_utils::BlendTowardOppositeLuminance(kBackgroundColor, alpha);
 }