Add pref for HTTP redirection limit.

The pref key name matches the associated Gecko pref key name.

components/net/http_loader.rs

@@ -44,6 +44,7 @@ use time::Tm;
 #[cfg(any(target_os = "macos", target_os = "linux"))]
 use tinyfiledialogs;
 use url::Url;
+use util::prefs;
 use util::resource_files::resources_dir_path;
 use util::thread::spawn_named;
 use uuid;
@@ -726,10 +727,7 @@ pub fn load<A, B>(load_data: LoadData,
                user_agent: String,
                cancel_listener: &CancellationListener)
                -> Result<StreamedResponse<A::R>, LoadError> where A: HttpRequest + 'static, B: UIProvider {
-    // FIXME: At the time of writing this FIXME, servo didn't have any central
-    //        location for configuration. If you're reading this and such a
-    //        repository DOES exist, please update this constant to use it.
-    let max_redirects = 50;
+    let max_redirects = prefs::get_pref("network.http.redirection-limit").as_i64().unwrap() as u32;
     let mut iters = 0;
     // URL of the document being loaded, as seen by all the higher-level code.
     let mut doc_url = load_data.url.clone();

resources/prefs.json

@@ -49,6 +49,7 @@
   "layout.text-orientation.enabled": false,
   "layout.viewport.enabled": false,
   "layout.writing-mode.enabled": false,
+  "network.http.redirection-limit": 50,
   "network.mime.sniff": false,
   "shell.native-titlebar.enabled": true,
   "shell.homepage": "http://servo.org"