[WebAPKs]: Reduce the parameters of ShortcutHelper::AddToLauncherWithSkBitmap()

chrome/browser/banners/app_banner_manager.cc

Index: chrome/browser/banners/app_banner_manager.cc
diff --git a/chrome/browser/banners/app_banner_manager.cc b/chrome/browser/banners/app_banner_manager.cc
index 156fa02630171a6a0357bb448a9b237a920c81f5..1eb2d4491c14b3e5c4ec5bfc372f1ee05a7d78db 100644
--- a/chrome/browser/banners/app_banner_manager.cc
+++ b/chrome/browser/banners/app_banner_manager.cc
@@ -140,11 +140,6 @@ void AppBannerManager::SendBannerDismissed(int request_id) {
   event_->BannerDismissed();
 }
 
-base::Closure AppBannerManager::FetchWebappSplashScreenImageCallback(
-    const std::string& webapp_id) {
-  return base::Closure();
-}
-
 AppBannerManager::AppBannerManager(content::WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
       SiteEngagementObserver(nullptr),