[evolution] Prefer OAuth2 authentication for Mail-only Google accounts

[Milan Crha <mcrha src gnome org>]

commit 3885b76176256e4d3b758617532454556748fa74
Author: Milan Crha <mcrha redhat com>
Date:   Wed Sep 7 10:39:10 2016 +0200

    Prefer OAuth2 authentication for Mail-only Google accounts
    
    When a Mail-only Google account had been created in the Evolution,
    it had set Plain password authentication, which requires an application
    specific password, while an OAuth2 could be used instead.

 modules/mail-config/e-mail-config-google-summary.c |   21 ++++++++++++++++++-
 1 files changed, 19 insertions(+), 2 deletions(-)
---
diff --git a/modules/mail-config/e-mail-config-google-summary.c 
b/modules/mail-config/e-mail-config-google-summary.c
index 1887ca5..0bbeb37 100644
--- a/modules/mail-config/e-mail-config-google-summary.c
+++ b/modules/mail-config/e-mail-config-google-summary.c
@@ -138,9 +138,26 @@ mail_config_google_summary_commit_changes_cb (EMailConfigSummaryPage *page,
                contacts_active = FALSE;
        }
 
-       /* If the user declined both Calendar and Contacts, do nothing. */
-       if (!calendar_active && !contacts_active)
+       /* If the user declined both Calendar and Contacts, do nothing,
+          but set the Google/OAuth2 authentication for the sources. */
+       if (!calendar_active && !contacts_active) {
+               if (e_source_credentials_google_is_supported ()) {
+                       source = e_mail_config_summary_page_get_account_source (page);
+                       auth_extension = e_source_get_extension (source, E_SOURCE_EXTENSION_AUTHENTICATION);
+                       e_source_authentication_set_method (auth_extension, "Google");
+
+                       head = g_queue_peek_head_link (source_queue);
+                       for (link = head; link != NULL; link = g_list_next (link)) {
+                               source = link->data;
+
+                               if (e_source_has_extension (source, E_SOURCE_EXTENSION_AUTHENTICATION)) {
+                                       auth_extension = e_source_get_extension (source, 
E_SOURCE_EXTENSION_AUTHENTICATION);
+                                       e_source_authentication_set_method (auth_extension, "Google");
+                               }
+                       }
+               }
                return;
+       }
 
        source = e_mail_config_summary_page_get_account_source (page);
        display_name = e_source_get_display_name (source);