Replace --add-to-shelf flag with kAppBanners feature.

chrome/browser/flag_descriptions.h

Index: chrome/browser/flag_descriptions.h
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index bd289b148eea2fb7633443a38e8da265f92a36e5..6d101470a1e4eeae5b19b95dfb474ea2a683391a 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -34,9 +34,6 @@ extern const char kAccelerated2dCanvasDescription[];
 extern const char kAcceleratedVideoDecodeName[];
 extern const char kAcceleratedVideoDecodeDescription[];
 
-extern const char kAddToShelfName[];
-extern const char kAddToShelfDescription[];
-
 extern const char kAffiliationBasedMatchingName[];
 extern const char kAffiliationBasedMatchingDescription[];
 
@@ -46,6 +43,9 @@ extern const char kAllowInsecureLocalhostDescription[];
 extern const char kAllowNaclSocketApiName[];
 extern const char kAllowNaclSocketApiDescription[];
 
+extern const char kAppBannersName[];
+extern const char kAppBannersDescription[];
+
 extern const char kAutoplayPolicyName[];
 extern const char kAutoplayPolicyDescription[];