MOBILE-3635 resource: Allow IFRAME to use XHTML

src/addons/mod/resource/services/resource-helper.ts

@@ -133,7 +133,7 @@ export class AddonModResourceHelperProvider {
             return false;
         }
 
-        return mimetype == 'text/html';
+        return mimetype == 'text/html' || mimetype == 'application/xhtml+xml';
     }
 
     /**

src/core/services/utils/iframe.ts

@@ -340,7 +340,7 @@ export class CoreIframeUtilsProvider {
 
             // Find the link being clicked.
             let el: Element | null = event.target as Element;
-            while (el && el.tagName !== 'A') {
+            while (el && el.tagName !== 'A' && el.tagName !== 'a') {
                 el = el.parentElement;
             }