Remove enable-iframe-based-signin flag.

components/signin/core/common/profile_management_switches.cc

Index: components/signin/core/common/profile_management_switches.cc
diff --git a/components/signin/core/common/profile_management_switches.cc b/components/signin/core/common/profile_management_switches.cc
index 42e78b45aa85aa6df9e486eff3ac3307ea1fe220..7c103b734524f39547f9436e09b665b6fec97ed6 100644
--- a/components/signin/core/common/profile_management_switches.cc
+++ b/components/signin/core/common/profile_management_switches.cc
@@ -110,16 +110,6 @@ bool IsEnableAccountConsistency() {
   return GetProcessState() >= STATE_ACCOUNT_CONSISTENCY;
 }
 
-bool IsEnableWebviewBasedSignin() {
-  // For now, the webview is enabled only for desktop.
-#if defined(OS_CHROMEOS)
-  return false;
-#else
-  return !base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableIframeBasedSignin);
-#endif
-}
-
 bool IsExtensionsMultiAccount() {
   return CheckFlag(switches::kExtensionsMultiAccount,
                    STATE_ACCOUNT_CONSISTENCY);