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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6 files changed, 7 insertions, 33 deletions

diff --git a/components/compositing/build.rs b/components/compositing/build.rs
index 54532276222..9803ce9480d 100644
--- a/components/compositing/build.rs
+++ b/components/compositing/build.rs
@@ -2,8 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-extern crate toml;
-
 use std::env;
 use std::fs::File;
 use std::io::{Read, Write};
diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index c3974c7fd01..ee25a835d7e 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -40,7 +40,6 @@ use style_traits::cursor::CursorKind;
 use style_traits::viewport::ViewportConstraints;
 use style_traits::{CSSPixel, DevicePixel, PinchZoomFactor};
 use time::{now, precise_time_ns, precise_time_s};
-use webrender;
 use webrender_api::{self, DeviceIntPoint, DevicePoint, HitTestFlags, HitTestResult};
 use webrender_api::{LayoutVector2D, ScrollLocation};
 
@@ -263,7 +262,7 @@ impl RenderNotifier {
 }
 
 impl webrender_api::RenderNotifier for RenderNotifier {
-    fn clone(&self) -> Box<webrender_api::RenderNotifier> {
+    fn clone(&self) -> Box<dyn webrender_api::RenderNotifier> {
         Box::new(RenderNotifier::new(self.compositor_proxy.clone()))
     }
 
diff --git a/components/compositing/compositor_thread.rs b/components/compositing/compositor_thread.rs
index a897f141fed..76b14d3eb6e 100644
--- a/components/compositing/compositor_thread.rs
+++ b/components/compositing/compositor_thread.rs
@@ -17,13 +17,12 @@ use script_traits::{AnimationState, ConstellationMsg, EventResult};
 use servo_channel::{Receiver, Sender};
 use std::fmt::{Debug, Error, Formatter};
 use style_traits::viewport::ViewportConstraints;
-use webrender;
 use webrender_api::{self, DeviceIntPoint, DeviceUintSize};
 
 /// Sends messages to the compositor.
 pub struct CompositorProxy {
     pub sender: Sender<Msg>,
-    pub event_loop_waker: Box<EventLoopWaker>,
+    pub event_loop_waker: Box<dyn EventLoopWaker>,
 }
 
 impl CompositorProxy {
@@ -98,7 +97,7 @@ pub enum Msg {
     /// Runs a closure in the compositor thread.
     /// It's used to dispatch functions from webrender to the main thread's event loop.
     /// Required to allow WGL GLContext sharing in Windows.
-    Dispatch(Box<Fn() + Send>),
+    Dispatch(Box<dyn Fn() + Send>),
     /// Indicates to the compositor that it needs to record the time when the frame with
     /// the given ID (epoch) is painted and report it to the layout thread of the given
     /// pipeline ID.
diff --git a/components/compositing/gl.rs b/components/compositing/gl.rs
index 6637ef203ea..59c1225cd91 100644
--- a/components/compositing/gl.rs
+++ b/components/compositing/gl.rs
@@ -14,7 +14,7 @@ pub struct RenderTargetInfo {
 }
 
 pub fn initialize_png(
-    gl: &gl::Gl,
+    gl: &dyn gl::Gl,
     width: DeviceUintLength,
     height: DeviceUintLength,
 ) -> RenderTargetInfo {
@@ -80,7 +80,7 @@ pub fn initialize_png(
 }
 
 pub fn draw_img(
-    gl: &gl::Gl,
+    gl: &dyn gl::Gl,
     render_target_info: RenderTargetInfo,
     width: DeviceUintLength,
     height: DeviceUintLength,
diff --git a/components/compositing/lib.rs b/components/compositing/lib.rs
index c631f39275e..d54feac56bb 100644
--- a/components/compositing/lib.rs
+++ b/components/compositing/lib.rs
@@ -4,30 +4,8 @@
 
 #![deny(unsafe_code)]
 
-extern crate embedder_traits;
-extern crate euclid;
-extern crate gfx_traits;
-#[cfg(feature = "gleam")]
-extern crate gleam;
-#[cfg(feature = "gleam")]
-extern crate image;
-extern crate ipc_channel;
-extern crate keyboard_types;
-extern crate libc;
 #[macro_use]
 extern crate log;
-extern crate msg;
-extern crate net_traits;
-extern crate profile_traits;
-extern crate script_traits;
-extern crate servo_channel;
-extern crate servo_config;
-extern crate servo_geometry;
-extern crate servo_url;
-extern crate style_traits;
-extern crate time;
-extern crate webrender;
-extern crate webrender_api;
 
 pub use crate::compositor::IOCompositor;
 pub use crate::compositor::RenderNotifier;
diff --git a/components/compositing/windowing.rs b/components/compositing/windowing.rs
index 9ff7e919746..087062c3fc2 100644
--- a/components/compositing/windowing.rs
+++ b/components/compositing/windowing.rs
@@ -132,9 +132,9 @@ pub trait WindowMethods {
     fn prepare_for_composite(&self) -> bool;
     /// Return the GL function pointer trait.
     #[cfg(feature = "gleam")]
-    fn gl(&self) -> Rc<gl::Gl>;
+    fn gl(&self) -> Rc<dyn gl::Gl>;
     /// Returns a thread-safe object to wake up the window's event loop.
-    fn create_event_loop_waker(&self) -> Box<EventLoopWaker>;
+    fn create_event_loop_waker(&self) -> Box<dyn EventLoopWaker>;
     /// Get the coordinates of the native window, the screen and the framebuffer.
     fn get_coordinates(&self) -> EmbedderCoordinates;
     /// Set whether the application is currently animating.