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 e5a14295bdf4f227c70f222e136b8b43346e5e3b..3fed699bd08b2444fff0620c2ec3af26601a4db3 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[];