[libgdata] app: Specify the correct content type

[Debarshi Ray <debarshir src gnome org>]

commit cdb623cac98509ce22d916ae9974fa6c3b21b7e6
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Feb 6 15:42:49 2017 +0100

    app: Specify the correct content type
    
    GDataAPPCategories supports only JSON ever since the YouTube API was
    ported to v3.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=777980

 gdata/app/gdata-app-categories.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/gdata/app/gdata-app-categories.c b/gdata/app/gdata-app-categories.c
index d271933..31585ff 100644
--- a/gdata/app/gdata-app-categories.c
+++ b/gdata/app/gdata-app-categories.c
@@ -45,6 +45,8 @@ parse_json (GDataParsable *parsable, JsonReader *reader, gpointer user_data,
             GError **error);
 static gboolean
 post_parse_json (GDataParsable *parsable, gpointer user_data, GError **error);
+static const gchar *
+get_content_type (void);
 
 struct _GDataAPPCategoriesPrivate {
        GList *categories;
@@ -72,6 +74,7 @@ gdata_app_categories_class_init (GDataAPPCategoriesClass *klass)
 
        parsable_class->parse_json = parse_json;
        parsable_class->post_parse_json = post_parse_json;
+       parsable_class->get_content_type = get_content_type;
 
        parsable_class->element_name = "categories";
        parsable_class->element_namespace = "app";
@@ -214,6 +217,12 @@ post_parse_json (GDataParsable *parsable, gpointer user_data, GError **error)
        return TRUE;
 }
 
+static const gchar *
+get_content_type (void)
+{
+       return "application/json";
+}
+
 /**
  * gdata_app_categories_get_categories:
  * @self: a #GDataAPPCategories