webapps: initial addition of splash screen icon downloading

chrome/browser/banners/app_banner_debug_log.cc

Index: chrome/browser/banners/app_banner_debug_log.cc
diff --git a/chrome/browser/banners/app_banner_debug_log.cc b/chrome/browser/banners/app_banner_debug_log.cc
index 0f56dd56223c8f529866506c78984ff20a7bc55b..f955cffe8532f90761bbd24994247520d4935a24 100644
--- a/chrome/browser/banners/app_banner_debug_log.cc
+++ b/chrome/browser/banners/app_banner_debug_log.cc
@@ -18,11 +18,15 @@ const char kRendererRequestCancel[] =
 const char kManifestEmpty[] = "manifest is empty or missing";
 const char kCannotDetermineBestIcon[] =
     "could not determine the best icon to use";
+const char kCannotDetermineBestSplashIcon[] =
+    "could not determine the best splashscreen icon to use";
 const char kNoMatchingServiceWorker[] =
     "no matching service worker detected. You may need to reload the page, or "
     "check that the service worker for the current page also controls the "
     "start URL from the manifest";
 const char kNoIconAvailable[] = "no icon available to display";
+const char kNoSplashIconAvailable[] =
+    "no splashscreen icon available to display";
 const char kBannerAlreadyAdded[] =
     "site requesting the banner has already been added";
 const char kUserNavigatedBeforeBannerShown[] =