[Autofill] Tweak credit card signin promo visually.

chrome/browser/ui/autofill/popup_constants.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_AUTOFILL_POPUP_CONSTANTS_H_
 #define CHROME_BROWSER_UI_AUTOFILL_POPUP_CONSTANTS_H_
 
+#include "third_party/skia/include/core/SkColor.h"
+
 namespace autofill {
 
 // The size of the border around the entire results popup, in pixels.
 const int kPopupBorderThickness = 1;
 
+// Various colors used in the Autofill popup.
+const SkColor kBorderColor = SkColorSetRGB(0xC7, 0xCA, 0xCE);
+const SkColor kHoveredBackgroundColor = SkColorSetRGB(0xCD, 0xCD, 0xCD);
+const SkColor kLabelTextColor = SkColorSetRGB(0x64, 0x64, 0x64);
+const SkColor kPromoPopupBackground = SkColorSetRGB(0xFA, 0xFA, 0xFA);
+const SkColor kWarningTextColor = SkColorSetRGB(0x64, 0x64, 0x64);
+constexpr SkColor kPopupBackground = SK_ColorWHITE;
+constexpr SkColor kValueTextColor = SK_ColorBLACK;
+
 }  // namespace autofill
 
 #endif  // CHROME_BROWSER_UI_AUTOFILL_POPUP_CONSTANTS_H_