Add a card background to the app list search result groups.

ui/app_list/app_list_constants.h

Index: ui/app_list/app_list_constants.h
diff --git a/ui/app_list/app_list_constants.h b/ui/app_list/app_list_constants.h
index 237114dcb13713b2b4c1d5d49a4c825365a1323c..da977d38786011b2b1077f5819336188eb2daf2c 100644
--- a/ui/app_list/app_list_constants.h
+++ b/ui/app_list/app_list_constants.h
@@ -43,6 +43,9 @@ APP_LIST_EXPORT extern const float kFolderBubbleRadius;
 APP_LIST_EXPORT extern const float kFolderShadowRadius;
 APP_LIST_EXPORT extern const float kFolderShadowOffsetY;
 
+APP_LIST_EXPORT extern const SkColor kCardShadowColor;
+APP_LIST_EXPORT extern const SkColor kCardBackgroundColor;
+
 APP_LIST_EXPORT extern const int kPageTransitionDurationInMs;
 APP_LIST_EXPORT extern const int kOverscrollPageTransitionDurationMs;
 APP_LIST_EXPORT extern const int kFolderTransitionInDurationMs;