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, 2 insertions, 3 deletions

diff --git a/components/script/dom/globalscope.rs b/components/script/dom/globalscope.rs
index 96d4131f581..5d2ed77ce4d 100644
--- a/components/script/dom/globalscope.rs
+++ b/components/script/dom/globalscope.rs
@@ -50,7 +50,6 @@ use js::rust::wrappers::Evaluate2;
 use js::rust::{get_object_class, CompileOptionsWrapper, Runtime};
 use js::rust::{HandleValue, MutableHandleValue};
 use js::{JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL};
-use libc;
 use msg::constellation_msg::PipelineId;
 use net_traits::{CoreResourceThread, IpcSend, ResourceThreads};
 use profile_traits::{mem as profile_mem, time as profile_time};
@@ -463,7 +462,7 @@ impl GlobalScope {
     }
 
     /// `ScriptChan` to send messages to the event loop of this global scope.
-    pub fn script_chan(&self) -> Box<ScriptChan + Send> {
+    pub fn script_chan(&self) -> Box<dyn ScriptChan + Send> {
         if let Some(window) = self.downcast::<Window>() {
             return MainThreadScriptChan(window.main_thread_script_chan().clone()).clone();
         }
@@ -663,7 +662,7 @@ impl GlobalScope {
     /// Create a new sender/receiver pair that can be used to implement an on-demand
     /// event loop. Used for implementing web APIs that require blocking semantics
     /// without resorting to nested event loops.
-    pub fn new_script_pair(&self) -> (Box<ScriptChan + Send>, Box<ScriptPort + Send>) {
+    pub fn new_script_pair(&self) -> (Box<dyn ScriptChan + Send>, Box<dyn ScriptPort + Send>) {
         if let Some(window) = self.downcast::<Window>() {
             return window.new_script_pair();
         }