MDL-58400 tool_mobile: Return enabled identity providers

Via this public Ajax Web Service we return the list of identity
providers in a site.

admin/tool/mobile/classes/api.php

@@ -153,6 +153,14 @@ class api {
             $settings['compactlogourl'] = $compactlogourl->out(false);
         }
 
+        // Identity providers.
+        $authsequence = get_enabled_auth_plugins(true);
+        $identityproviders = \auth_plugin_base::get_identity_providers($authsequence);
+        $identityprovidersdata = \auth_plugin_base::prepare_identity_providers_for_output($identityproviders, $OUTPUT);
+        if (!empty($identityprovidersdata)) {
+            $settings['identityproviders'] = $identityprovidersdata;
+        }
+
         return $settings;
     }
 

admin/tool/mobile/classes/external.php

@@ -150,6 +150,16 @@ class external extends external_api {
                 'launchurl' => new external_value(PARAM_URL, 'SSO login launch URL. Empty if it won\'t be used.', VALUE_OPTIONAL),
                 'mobilecssurl' => new external_value(PARAM_URL, 'Mobile custom CSS theme', VALUE_OPTIONAL),
                 'tool_mobile_disabledfeatures' => new external_value(PARAM_RAW, 'Disabled features in the app', VALUE_OPTIONAL),
+                'identityproviders' => new external_multiple_structure(
+                    new external_single_structure(
+                        array(
+                            'name' => new external_value(PARAM_TEXT, 'The identity provider name.'),
+                            'iconurl' => new external_value(PARAM_URL, 'The icon URL for the provider.'),
+                            'url' => new external_value(PARAM_URL, 'The URL of the provider.'),
+                        )
+                    ),
+                    'Identity providers', VALUE_OPTIONAL
+                ),
                 'warnings' => new external_warnings(),
             )
         );

admin/tool/mobile/upgrade.txt

@@ -4,4 +4,5 @@ Information provided here is intended especially for developers.
 === 3.3 ===
 
  * External function tool_mobile::get_public_config now returns the mobilecssurl field (Mobile custom CSS theme).
+ * External function tool_mobile::get_public_config now returns the identityproviders field (list of external identity providers).