[Clean-up] Remove some dead code for handling Webstore sign-in.

chrome/browser/signin/signin_promo.h

Index: chrome/browser/signin/signin_promo.h
diff --git a/chrome/browser/signin/signin_promo.h b/chrome/browser/signin/signin_promo.h
index 62bef7effeade04429f920801f1d51974c363656..120661a44c2d9179f43aa95f2c59d7781a0f3ce3 100644
--- a/chrome/browser/signin/signin_promo.h
+++ b/chrome/browser/signin/signin_promo.h
@@ -32,7 +32,6 @@ enum Source {
   SOURCE_MENU,
   SOURCE_SETTINGS,
   SOURCE_EXTENSION_INSTALL_BUBBLE,
-  SOURCE_WEBSTORE_INSTALL,
   SOURCE_APP_LAUNCHER,
   SOURCE_APPS_PAGE_LINK,
   SOURCE_BOOKMARK_BUBBLE,
@@ -89,13 +88,6 @@ GURL GetLandingURL(const char* option, int value);
 GURL GetPromoURL(Source source, bool auto_close);
 GURL GetPromoURL(Source source, bool auto_close, bool is_constrained);
 
-// As above, but also appends the |continue_url| as a parameter to the URL.
-// A |continue_url| may be set only when not using the web-based sign-in flow.
-GURL GetPromoURLWithContinueURL(Source source,
-                                bool auto_close,
-                                bool is_constrained,
-                                GURL continue_url);
-
 // Returns a sign in promo URL specifically for reauthenticating |account_id|.
 GURL GetReauthURL(Profile* profile, const std::string& account_id);