[Autofill] Tweak credit card signin promo visually.

chrome/browser/ui/autofill/autofill_popup_controller.h

Index: chrome/browser/ui/autofill/autofill_popup_controller.h
diff --git a/chrome/browser/ui/autofill/autofill_popup_controller.h b/chrome/browser/ui/autofill/autofill_popup_controller.h
index df17ce6b39c19e02667c222049ecb3317c3647d0..b2b98b4b211252336b4b3417b75a09f0b93afe4f 100644
--- a/chrome/browser/ui/autofill/autofill_popup_controller.h
+++ b/chrome/browser/ui/autofill/autofill_popup_controller.h
@@ -13,6 +13,7 @@
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "chrome/browser/ui/autofill/autofill_popup_view_delegate.h"
+#include "third_party/skia/include/core/SkColor.h"
 
 namespace gfx {
 class FontList;
@@ -62,6 +63,10 @@ class AutofillPopupController : public AutofillPopupViewDelegate {
   virtual const gfx::FontList& GetLabelFontList() const = 0;
 #endif
 
+  // Returns the background color of the row item according to its |index|, or
+  // transparent if the default popup background should be used.
+  virtual SkColor GetBackgroundColorForRow(int index) const = 0;
+
   // Returns the index of the selected line. A line is "selected" when it is
   // hovered or has keyboard focus.
   virtual int selected_line() const = 0;