Remove support for special "sign in process" state.

components/signin/core/browser/signin_manager.h

Index: components/signin/core/browser/signin_manager.h
diff --git a/components/signin/core/browser/signin_manager.h b/components/signin/core/browser/signin_manager.h
index f8f9f2a0fe55ffa8fad23d3f39e8ead83c84cec7..631cab2dea7e6e479ac1ddc6a2f1a226a3131572 100644
--- a/components/signin/core/browser/signin_manager.h
+++ b/components/signin/core/browser/signin_manager.h
@@ -55,10 +55,6 @@ class SigninManager : public SigninManagerBase,
   // signin. The callback is passed the just-fetched OAuth login refresh token.
   typedef base::Callback<void(const std::string&)> OAuthTokenFetchedCallback;
 
-  // Returns true if |url| is a web signin URL and should be hosted in an
-  // isolated, privileged signin process.
-  static bool IsWebBasedSigninFlowURL(const GURL& url);
-
   // This is used to distinguish URLs belonging to the special web signin flow
   // running in the special signin process from other URLs on the same domain.
   // We do not grant WebUI privilieges / bindings to this process or to URLs of