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, 35 insertions, 53 deletions

diff --git a/components/canvas/canvas_data.rs b/components/canvas/canvas_data.rs
index 97e2dee4800..d07ee2cd9cf 100644
--- a/components/canvas/canvas_data.rs
+++ b/components/canvas/canvas_data.rs
@@ -15,11 +15,9 @@ use cssparser::RGBA;
 use euclid::{Point2D, Rect, Size2D, Transform2D, Vector2D};
 use ipc_channel::ipc::IpcSender;
 use num_traits::ToPrimitive;
-use pixels;
 use serde_bytes::ByteBuf;
 use std::mem;
 use std::sync::Arc;
-use webrender_api;
 
 pub struct CanvasData<'a> {
     drawtarget: DrawTarget,
diff --git a/components/canvas/canvas_paint_thread.rs b/components/canvas/canvas_paint_thread.rs
index 7baef384ae9..d4f00506a3e 100644
--- a/components/canvas/canvas_paint_thread.rs
+++ b/components/canvas/canvas_paint_thread.rs
@@ -10,7 +10,6 @@ use ipc_channel::ipc::{self, IpcSender};
 use std::borrow::ToOwned;
 use std::collections::HashMap;
 use std::thread;
-use webrender_api;
 
 pub struct CanvasPaintThread<'a> {
     canvases: HashMap<CanvasId, CanvasData<'a>>,
diff --git a/components/canvas/gl_context.rs b/components/canvas/gl_context.rs
index 077ea3b7f9f..9f8aeb2fe31 100644
--- a/components/canvas/gl_context.rs
+++ b/components/canvas/gl_context.rs
@@ -169,7 +169,7 @@ impl GLContextWrapper {
         }
     }
 
-    pub fn gl(&self) -> &gl::Gl {
+    pub fn gl(&self) -> &dyn gl::Gl {
         match *self {
             GLContextWrapper::Native(ref ctx) => ctx.gl(),
             GLContextWrapper::OSMesa(ref ctx) => ctx.gl(),
@@ -236,7 +236,7 @@ impl MainThreadDispatcher {
     }
 }
 impl GLContextDispatcher for MainThreadDispatcher {
-    fn dispatch(&self, f: Box<Fn() + Send>) {
+    fn dispatch(&self, f: Box<dyn Fn() + Send>) {
         self.compositor_proxy
             .lock()
             .unwrap()
diff --git a/components/canvas/lib.rs b/components/canvas/lib.rs
index 2e42b7e1902..ab785a5620c 100644
--- a/components/canvas/lib.rs
+++ b/components/canvas/lib.rs
@@ -4,23 +4,8 @@
 
 #![deny(unsafe_code)]
 
-extern crate azure;
-extern crate canvas_traits;
-extern crate compositing;
-extern crate cssparser;
-extern crate euclid;
-extern crate fnv;
-extern crate gleam;
-extern crate ipc_channel;
 #[macro_use]
 extern crate log;
-extern crate num_traits;
-extern crate offscreen_gl_context;
-extern crate pixels;
-extern crate serde_bytes;
-extern crate servo_config;
-extern crate webrender;
-extern crate webrender_api;
 
 pub mod canvas_data;
 pub mod canvas_paint_thread;
diff --git a/components/canvas/webgl_mode/inprocess.rs b/components/canvas/webgl_mode/inprocess.rs
index 1f7ade4eb56..8200d4dde3e 100644
--- a/components/canvas/webgl_mode/inprocess.rs
+++ b/components/canvas/webgl_mode/inprocess.rs
@@ -13,8 +13,6 @@ use fnv::FnvHashMap;
 use gleam::gl;
 use servo_config::prefs::PREFS;
 use std::rc::Rc;
-use webrender;
-use webrender_api;
 
 /// WebGL Threading API entry point that lives in the constellation.
 pub struct WebGLThreads(WebGLSender<WebGLMsg>);
@@ -23,13 +21,13 @@ impl WebGLThreads {
     /// Creates a new WebGLThreads object
     pub fn new(
         gl_factory: GLContextFactory,
-        webrender_gl: Rc<gl::Gl>,
+        webrender_gl: Rc<dyn gl::Gl>,
         webrender_api_sender: webrender_api::RenderApiSender,
-        webvr_compositor: Option<Box<WebVRRenderHandler>>,
+        webvr_compositor: Option<Box<dyn WebVRRenderHandler>>,
     ) -> (
         WebGLThreads,
-        Box<webrender::ExternalImageHandler>,
-        Option<Box<webrender::OutputImageHandler>>,
+        Box<dyn webrender::ExternalImageHandler>,
+        Option<Box<dyn webrender::OutputImageHandler>>,
     ) {
         // This implementation creates a single `WebGLThread` for all the pipelines.
         let channel = WebGLThread::start(
@@ -70,7 +68,7 @@ impl WebGLThreads {
 
 /// Bridge between the webrender::ExternalImage callbacks and the WebGLThreads.
 struct WebGLExternalImages {
-    webrender_gl: Rc<gl::Gl>,
+    webrender_gl: Rc<dyn gl::Gl>,
     webgl_channel: WebGLSender<WebGLMsg>,
     // Used to avoid creating a new channel on each received WebRender request.
     lock_channel: (
@@ -80,7 +78,7 @@ struct WebGLExternalImages {
 }
 
 impl WebGLExternalImages {
-    fn new(webrender_gl: Rc<gl::Gl>, channel: WebGLSender<WebGLMsg>) -> Self {
+    fn new(webrender_gl: Rc<dyn gl::Gl>, channel: WebGLSender<WebGLMsg>) -> Self {
         Self {
             webrender_gl,
             webgl_channel: channel,
@@ -111,7 +109,7 @@ impl WebGLExternalImageApi for WebGLExternalImages {
 }
 
 /// Wrapper to send WebVR commands used in `WebGLThread`.
-struct WebVRRenderWrapper(Box<WebVRRenderHandler>);
+struct WebVRRenderWrapper(Box<dyn WebVRRenderHandler>);
 
 impl WebVRRenderHandler for WebVRRenderWrapper {
     fn handle(&mut self, command: WebVRCommand, texture: Option<(u32, Size2D<i32>)>) {
@@ -122,7 +120,7 @@ impl WebVRRenderHandler for WebVRRenderWrapper {
 /// struct used to implement DOMToTexture feature and webrender::OutputImageHandler trait.
 type OutputHandlerData = Option<(u32, Size2D<i32>)>;
 struct OutputHandler {
-    webrender_gl: Rc<gl::Gl>,
+    webrender_gl: Rc<dyn gl::Gl>,
     webgl_channel: WebGLSender<WebGLMsg>,
     // Used to avoid creating a new channel on each received WebRender request.
     lock_channel: (
@@ -133,7 +131,7 @@ struct OutputHandler {
 }
 
 impl OutputHandler {
-    fn new(webrender_gl: Rc<gl::Gl>, channel: WebGLSender<WebGLMsg>) -> Self {
+    fn new(webrender_gl: Rc<dyn gl::Gl>, channel: WebGLSender<WebGLMsg>) -> Self {
         Self {
             webrender_gl,
             webgl_channel: channel,
diff --git a/components/canvas/webgl_thread.rs b/components/canvas/webgl_thread.rs
index e47bfffdbcc..dec2ad33263 100644
--- a/components/canvas/webgl_thread.rs
+++ b/components/canvas/webgl_thread.rs
@@ -8,10 +8,7 @@ use euclid::Size2D;
 use fnv::FnvHashMap;
 use gleam::gl;
 use offscreen_gl_context::{GLContext, GLContextAttributes, GLLimits, NativeGLContextMethods};
-use pixels;
 use std::thread;
-use webrender;
-use webrender_api;
 
 /// WebGL Threading API entry point that lives in the constellation.
 /// It allows to get a WebGLThread handle for each script pipeline.
@@ -1364,7 +1361,7 @@ impl WebGLImpl {
     }
 
     fn initialize_framebuffer(
-        gl: &gl::Gl,
+        gl: &dyn gl::Gl,
         state: &GLState,
         color: bool,
         depth: bool,
@@ -1424,7 +1421,7 @@ impl WebGLImpl {
     }
 
     #[allow(unsafe_code)]
-    fn link_program(gl: &gl::Gl, program: WebGLProgramId) -> ProgramLinkInfo {
+    fn link_program(gl: &dyn gl::Gl, program: WebGLProgramId) -> ProgramLinkInfo {
         gl.link_program(program.get());
         let mut linked = [0];
         unsafe {
@@ -1497,13 +1494,13 @@ impl WebGLImpl {
         }
     }
 
-    fn finish(gl: &gl::Gl, chan: &WebGLSender<()>) {
+    fn finish(gl: &dyn gl::Gl, chan: &WebGLSender<()>) {
         gl.finish();
         chan.send(()).unwrap();
     }
 
     fn shader_precision_format(
-        gl: &gl::Gl,
+        gl: &dyn gl::Gl,
         shader_type: u32,
         precision_type: u32,
         chan: &WebGLSender<(i32, i32, i32)>,
@@ -1512,13 +1509,13 @@ impl WebGLImpl {
         chan.send(result).unwrap();
     }
 
-    fn get_extensions(gl: &gl::Gl, chan: &WebGLSender<String>) {
+    fn get_extensions(gl: &dyn gl::Gl, chan: &WebGLSender<String>) {
         chan.send(gl.get_string(gl::EXTENSIONS)).unwrap();
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.6
     fn get_framebuffer_attachment_parameter(
-        gl: &gl::Gl,
+        gl: &dyn gl::Gl,
         target: u32,
         attachment: u32,
         pname: u32,
@@ -1529,13 +1526,18 @@ impl WebGLImpl {
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.7
-    fn get_renderbuffer_parameter(gl: &gl::Gl, target: u32, pname: u32, chan: &WebGLSender<i32>) {
+    fn get_renderbuffer_parameter(
+        gl: &dyn gl::Gl,
+        target: u32,
+        pname: u32,
+        chan: &WebGLSender<i32>,
+    ) {
         let parameter = gl.get_renderbuffer_parameter_iv(target, pname);
         chan.send(parameter).unwrap();
     }
 
     fn uniform_location(
-        gl: &gl::Gl,
+        gl: &dyn gl::Gl,
         program_id: WebGLProgramId,
         name: &str,
         chan: &WebGLSender<i32>,
@@ -1545,18 +1547,18 @@ impl WebGLImpl {
         chan.send(location).unwrap();
     }
 
-    fn shader_info_log(gl: &gl::Gl, shader_id: WebGLShaderId, chan: &WebGLSender<String>) {
+    fn shader_info_log(gl: &dyn gl::Gl, shader_id: WebGLShaderId, chan: &WebGLSender<String>) {
         let log = gl.get_shader_info_log(shader_id.get());
         chan.send(log).unwrap();
     }
 
-    fn program_info_log(gl: &gl::Gl, program_id: WebGLProgramId, chan: &WebGLSender<String>) {
+    fn program_info_log(gl: &dyn gl::Gl, program_id: WebGLProgramId, chan: &WebGLSender<String>) {
         let log = gl.get_program_info_log(program_id.get());
         chan.send(log).unwrap();
     }
 
     #[allow(unsafe_code)]
-    fn create_buffer(gl: &gl::Gl, chan: &WebGLSender<Option<WebGLBufferId>>) {
+    fn create_buffer(gl: &dyn gl::Gl, chan: &WebGLSender<Option<WebGLBufferId>>) {
         let buffer = gl.gen_buffers(1)[0];
         let buffer = if buffer == 0 {
             None
@@ -1567,7 +1569,7 @@ impl WebGLImpl {
     }
 
     #[allow(unsafe_code)]
-    fn create_framebuffer(gl: &gl::Gl, chan: &WebGLSender<Option<WebGLFramebufferId>>) {
+    fn create_framebuffer(gl: &dyn gl::Gl, chan: &WebGLSender<Option<WebGLFramebufferId>>) {
         let framebuffer = gl.gen_framebuffers(1)[0];
         let framebuffer = if framebuffer == 0 {
             None
@@ -1578,7 +1580,7 @@ impl WebGLImpl {
     }
 
     #[allow(unsafe_code)]
-    fn create_renderbuffer(gl: &gl::Gl, chan: &WebGLSender<Option<WebGLRenderbufferId>>) {
+    fn create_renderbuffer(gl: &dyn gl::Gl, chan: &WebGLSender<Option<WebGLRenderbufferId>>) {
         let renderbuffer = gl.gen_renderbuffers(1)[0];
         let renderbuffer = if renderbuffer == 0 {
             None
@@ -1589,7 +1591,7 @@ impl WebGLImpl {
     }
 
     #[allow(unsafe_code)]
-    fn create_texture(gl: &gl::Gl, chan: &WebGLSender<Option<WebGLTextureId>>) {
+    fn create_texture(gl: &dyn gl::Gl, chan: &WebGLSender<Option<WebGLTextureId>>) {
         let texture = gl.gen_textures(1)[0];
         let texture = if texture == 0 {
             None
@@ -1600,7 +1602,7 @@ impl WebGLImpl {
     }
 
     #[allow(unsafe_code)]
-    fn create_program(gl: &gl::Gl, chan: &WebGLSender<Option<WebGLProgramId>>) {
+    fn create_program(gl: &dyn gl::Gl, chan: &WebGLSender<Option<WebGLProgramId>>) {
         let program = gl.create_program();
         let program = if program == 0 {
             None
@@ -1611,7 +1613,7 @@ impl WebGLImpl {
     }
 
     #[allow(unsafe_code)]
-    fn create_shader(gl: &gl::Gl, shader_type: u32, chan: &WebGLSender<Option<WebGLShaderId>>) {
+    fn create_shader(gl: &dyn gl::Gl, shader_type: u32, chan: &WebGLSender<Option<WebGLShaderId>>) {
         let shader = gl.create_shader(shader_type);
         let shader = if shader == 0 {
             None
@@ -1622,7 +1624,7 @@ impl WebGLImpl {
     }
 
     #[allow(unsafe_code)]
-    fn create_vertex_array(gl: &gl::Gl, chan: &WebGLSender<Option<WebGLVertexArrayId>>) {
+    fn create_vertex_array(gl: &dyn gl::Gl, chan: &WebGLSender<Option<WebGLVertexArrayId>>) {
         let vao = gl.gen_vertex_arrays(1)[0];
         let vao = if vao == 0 {
             None
@@ -1634,7 +1636,7 @@ impl WebGLImpl {
 
     #[inline]
     fn bind_framebuffer<Native: NativeGLContextMethods>(
-        gl: &gl::Gl,
+        gl: &dyn gl::Gl,
         target: u32,
         request: WebGLFramebufferBindingRequest,
         ctx: &GLContext<Native>,
@@ -1650,7 +1652,7 @@ impl WebGLImpl {
     }
 
     #[inline]
-    fn compile_shader(gl: &gl::Gl, shader_id: WebGLShaderId, source: &str) {
+    fn compile_shader(gl: &dyn gl::Gl, shader_id: WebGLShaderId, source: &str) {
         gl.shader_source(shader_id.get(), &[source.as_bytes()]);
         gl.compile_shader(shader_id.get());
     }