Remove icon bg color for message center notifications.

ui/message_center/views/notification_view.cc

Index: ui/message_center/views/notification_view.cc
diff --git a/ui/message_center/views/notification_view.cc b/ui/message_center/views/notification_view.cc
index 4e6246c675276a98ff6ac714740a3f800e20b9c9..4464be37a4728736cf6babba91c0baa9c9fda872 100644
--- a/ui/message_center/views/notification_view.cc
+++ b/ui/message_center/views/notification_view.cc
@@ -580,13 +580,6 @@ void NotificationView::CreateOrUpdateIconView(
 
   gfx::ImageSkia icon = notification.icon().AsImageSkia();
   icon_view_->SetImage(icon, icon.size());
-
-  if (notification.draw_icon_background()) {
-    icon_view_->set_background(
-        views::Background::CreateSolidBackground(kIconBackgroundColor));
-  } else {
-    icon_view_->set_background(nullptr);
-  }
 }
 
 void NotificationView::CreateOrUpdateImageView(