Auto merge of #12178 - frewsxcv:prefs, r=emilio

Refactor `util::prefs` operations to be methods on static struct.

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- [ ] These changes fix #__ (github issue number if applicable).

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components/net/http_loader.rs

@@ -51,7 +51,7 @@ use time::Tm;
 #[cfg(any(target_os = "macos", target_os = "linux"))]
 use tinyfiledialogs;
 use url::{Url, Position};
-use util::prefs;
+use util::prefs::PREFS;
 use util::thread::spawn_named;
 use uuid;
 
@@ -860,7 +860,7 @@ pub fn load<A, B>(load_data: &LoadData,
                   user_agent: String,
                   cancel_listener: &CancellationListener)
                   -> Result<StreamedResponse, LoadError> where A: HttpRequest + 'static, B: UIProvider {
-    let max_redirects = prefs::get_pref("network.http.redirection-limit").as_i64().unwrap() as u32;
+    let max_redirects = PREFS.get("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();

components/net/resource_thread.rs

@@ -48,7 +48,7 @@ use std::sync::{Arc, RwLock};
 use storage_thread::StorageThreadFactory;
 use url::Url;
 use util::opts;
-use util::prefs;
+use util::prefs::PREFS;
 use util::thread::spawn_named;
 use websocket_loader;
 
@@ -106,7 +106,7 @@ pub fn start_sending_sniffed_opt(start_chan: LoadConsumer, mut metadata: Metadat
                                  classifier: Arc<MIMEClassifier>, partial_body: &[u8],
                                  context: LoadContext)
                                  -> Result<ProgressSender, ()> {
-    if prefs::get_pref("network.mime.sniff").as_boolean().unwrap_or(false) {
+    if PREFS.get("network.mime.sniff").as_boolean().unwrap_or(false) {
         // TODO: should be calculated in the resource loader, from pull requeset #4094
         let mut no_sniff = NoSniffFlag::OFF;
         let mut check_for_apache_bug = ApacheBugFlag::OFF;