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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3 files changed, 3 insertions, 26 deletions

diff --git a/components/script_layout_interface/lib.rs b/components/script_layout_interface/lib.rs
index 58695a27750..3bdd0830cfb 100644
--- a/components/script_layout_interface/lib.rs
+++ b/components/script_layout_interface/lib.rs
@@ -9,34 +9,12 @@
 #![deny(unsafe_code)]
 #![feature(associated_type_defaults)]
 
-extern crate app_units;
-extern crate atomic_refcell;
-extern crate canvas_traits;
-extern crate cssparser;
-extern crate euclid;
-extern crate gfx_traits;
 #[macro_use]
 extern crate html5ever;
-extern crate ipc_channel;
-extern crate libc;
 #[macro_use]
 extern crate log;
-extern crate malloc_size_of;
 #[macro_use]
 extern crate malloc_size_of_derive;
-extern crate metrics;
-extern crate msg;
-extern crate net_traits;
-extern crate profile_traits;
-extern crate range;
-extern crate script_traits;
-extern crate selectors;
-extern crate servo_arc;
-extern crate servo_atoms;
-extern crate servo_channel;
-extern crate servo_url;
-extern crate style;
-extern crate webrender_api;
 
 pub mod message;
 pub mod reporter;
diff --git a/components/script_layout_interface/message.rs b/components/script_layout_interface/message.rs
index 01edca28a77..5c504d06e84 100644
--- a/components/script_layout_interface/message.rs
+++ b/components/script_layout_interface/message.rs
@@ -42,7 +42,7 @@ pub enum Msg {
     Reflow(ScriptReflow),
 
     /// Get an RPC interface.
-    GetRPC(Sender<Box<LayoutRPC + Send>>),
+    GetRPC(Sender<Box<dyn LayoutRPC + Send>>),
 
     /// Requests that the layout thread render the next frame of all animations.
     TickAnimations,
@@ -94,7 +94,7 @@ pub enum Msg {
     UpdateScrollStateFromScript(ScrollState),
 
     /// Tells layout that script has added some paint worklet modules.
-    RegisterPaint(Atom, Vec<Atom>, Box<Painter>),
+    RegisterPaint(Atom, Vec<Atom>, Box<dyn Painter>),
 
     /// Send to layout the precise time when the navigation started.
     SetNavigationStart(u64),
@@ -214,7 +214,7 @@ pub struct NewLayoutThreadInfo {
     pub pipeline_port: IpcReceiver<LayoutControlMsg>,
     pub constellation_chan: IpcSender<ConstellationMsg>,
     pub script_chan: IpcSender<ConstellationControlMsg>,
-    pub image_cache: Arc<ImageCache>,
+    pub image_cache: Arc<dyn ImageCache>,
     pub content_process_shutdown_chan: Option<IpcSender<()>>,
     pub layout_threads: usize,
     pub paint_time_metrics: PaintTimeMetrics,
diff --git a/components/script_layout_interface/reporter.rs b/components/script_layout_interface/reporter.rs
index ac52cde8012..3c4f024d2f2 100644
--- a/components/script_layout_interface/reporter.rs
+++ b/components/script_layout_interface/reporter.rs
@@ -4,7 +4,6 @@
 
 use cssparser::SourceLocation;
 use ipc_channel::ipc::IpcSender;
-use log;
 use msg::constellation_msg::PipelineId;
 use script_traits::ConstellationControlMsg;
 use servo_url::ServoUrl;