Auto merge of #22133 - servo:extern-crate, r=SimonSapin

Use 2018-edition idioms in crates that use that edition

The first commit is almost entirely mechanical, created by running `cargo fix --edition-idioms` and relevant crates. I undid the change of adding an anonymous lifetime parameter in types that have implicit lifetimes parameters, for example replacing `&mut Formatter` with `&mut Formatter<'_>`, because I don’t like it. The remaining changes are, in many places:

* Add `dyn` to trait object types, for example `Rc<gl::Gl>` to `Rc<dyn gl::Gl>`. This change also works in the 2015 edition.
* Remove `extern crate` where is it made unneeded by changes to the import/module system.

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1 files changed, 1 insertions, 3 deletions

diff --git a/components/net/resource_thread.rs b/components/net/resource_thread.rs
index 9793fcb862d..0ae1f548525 100644
--- a/components/net/resource_thread.rs
+++ b/components/net/resource_thread.rs
@@ -3,9 +3,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 //! A thread that takes a URL and streams back the binary data.
+
 use crate::connector::{create_http_client, create_ssl_connector_builder};
 use crate::cookie;
-use crate::cookie_rs;
 use crate::cookie_storage::CookieStorage;
 use crate::fetch::cors_cache::CorsCache;
 use crate::fetch::methods::{fetch, CancellationListener, FetchContext};
@@ -32,8 +32,6 @@ use profile_traits::mem::ProfilerChan as MemProfilerChan;
 use profile_traits::mem::{Report, ReportKind, ReportsChan};
 use profile_traits::time::ProfilerChan;
 use serde::{Deserialize, Serialize};
-use serde_json;
-use servo_allocator;
 use servo_channel::Sender;
 use servo_config::opts;
 use servo_url::ServoUrl;