Adding ChromeIdentity in ShowSigninCommand.

ios/chrome/browser/ui/commands/show_signin_command.mm

Index: ios/chrome/browser/ui/commands/show_signin_command.mm
diff --git a/ios/chrome/browser/ui/commands/show_signin_command.mm b/ios/chrome/browser/ui/commands/show_signin_command.mm
index cc78ed679801f2547cc495a6858f587f71eaa8d9..e2fc2c69664df63a99cc4e2049865f9e166a564b 100644
--- a/ios/chrome/browser/ui/commands/show_signin_command.mm
+++ b/ios/chrome/browser/ui/commands/show_signin_command.mm
@@ -14,6 +14,7 @@
 @implementation ShowSigninCommand
 
 @synthesize operation = _operation;
+@synthesize identity = _identity;
 @synthesize accessPoint = _accessPoint;
 @synthesize promoAction = _promoAction;
 @synthesize callback = _callback;
@@ -24,12 +25,15 @@
 }
 
 - (instancetype)initWithOperation:(AuthenticationOperation)operation
+                         identity:(ChromeIdentity*)identity
                       accessPoint:(signin_metrics::AccessPoint)accessPoint
                       promoAction:(signin_metrics::PromoAction)promoAction
                          callback:
                              (ShowSigninCommandCompletionCallback)callback {
   if ((self = [super initWithTag:IDC_SHOW_SIGNIN_IOS])) {
+    DCHECK(operation == AUTHENTICATION_OPERATION_SIGNIN || identity == nil);
     _operation = operation;
+    _identity = identity;
     _accessPoint = accessPoint;
     _promoAction = promoAction;
     _callback = [callback copy];
@@ -41,6 +45,7 @@
                       accessPoint:(signin_metrics::AccessPoint)accessPoint
                       promoAction:(signin_metrics::PromoAction)promoAction {
   return [self initWithOperation:operation
+                        identity:nil
                      accessPoint:accessPoint
                      promoAction:promoAction
                         callback:nil];
@@ -49,6 +54,7 @@
 - (instancetype)initWithOperation:(AuthenticationOperation)operation
                       accessPoint:(signin_metrics::AccessPoint)accessPoint {
   return [self initWithOperation:operation
+                        identity:nil
                      accessPoint:accessPoint
                      promoAction:signin_metrics::PromoAction::
                                      PROMO_ACTION_NO_SIGNIN_PROMO