[iOS] Removes deprecated method from SigninEarlGreyUI.

Removes method confirmSigninConfirmationDialog from SigninEarlGreyUI.

Bug: 1103274
Change-Id: I6c1aead8dbd94e0a5f760c83139af4f99c0e1098
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2364633
Commit-Queue: Nohemi Fernandez <fernandex@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799955}

ios/chrome/browser/ui/authentication/signin_earl_grey_ui.h

@@ -39,9 +39,6 @@
 // opened before calling this method.
 + (void)tapSettingsLink;
 
-// Deprecated. Use |tapSigninConfirmationDialog|.
-+ (void)confirmSigninConfirmationDialog;
-
 // Taps the sign in confirmation page, scrolls first to make the OK button
 // visible on short devices (e.g. iPhone 5s).
 + (void)tapSigninConfirmationDialog;

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

@@ -87,10 +87,6 @@ using chrome_test_util::SignOutAccountsButton;
       performAction:grey_tap()];
 }
 
-+ (void)confirmSigninConfirmationDialog {
-  [self tapSigninConfirmationDialog];
-}
-
 + (void)tapSigninConfirmationDialog {
   // To confirm the dialog, the scroll view content has to be scrolled to the
   // bottom to transform "MORE" button into the validation button.