Adding ChromeIdentity in ShowSigninCommand.

ios/chrome/browser/ui/authentication/signin_promo_view_mediator.mm

Index: ios/chrome/browser/ui/authentication/signin_promo_view_mediator.mm
diff --git a/ios/chrome/browser/ui/authentication/signin_promo_view_mediator.mm b/ios/chrome/browser/ui/authentication/signin_promo_view_mediator.mm
index 96bb2ecc11b9dce014a0711c192d749bca4c8627..885d1044fa21dd1d2db6ab643478ce18c6e5a3ef 100644
--- a/ios/chrome/browser/ui/authentication/signin_promo_view_mediator.mm
+++ b/ios/chrome/browser/ui/authentication/signin_promo_view_mediator.mm
@@ -207,8 +207,10 @@ void RecordSigninNewAccountUserActionForAccessPoint(
   RecordSigninDefaultUserActionForAccessPoint(_accessPoint);
   ShowSigninCommand* command = [[ShowSigninCommand alloc]
       initWithOperation:AUTHENTICATION_OPERATION_SIGNIN_PROMO_CONTINUE_AS

[msarda, 2017/05/16 13:33:53]

Use AUTHENTICATION_OPERATION_SIGNIN.

[jlebel, 2017/05/16 17:55:08]

Done.

+               identity:_defaultIdentity
             accessPoint:_accessPoint
-            promoAction:signin_metrics::PromoAction::PROMO_ACTION_WITH_DEFAULT];
+            promoAction:signin_metrics::PromoAction::PROMO_ACTION_WITH_DEFAULT
+               callback:nil];

[msarda, 2017/05/16 13:33:53]

Remove "callback" (it is nil by default).

[jlebel, 2017/05/16 17:55:08]

-[ShowSigninCommand initWithOperation:identity:accessPoint:promoAction:] doesn't
exist. I'm not sure it is relevant to create this method since it is used only
once.
I would prefer to keep it that way if it is ok with you.

   [signinPromoView chromeExecuteCommand:command];
 }