Auto merge of #17891 - MortimerGoro:webgl_move, r=glennw,emilio

Improved WebGL architecture

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Info about the big picture and the goals of the WebGL refactor in this thread: https://groups.google.com/forum/#!topic/mozilla.dev.servo/0WMGz60kKzQ

I tried to reduce this PR as much as possible as requested in the thread. I'll do separate PRs for other features (e.g.: Batch messages or use shared memory to improve frame times) or fixes.

Some tips to ease the review process:
- Most changes in DOM objects follow the same pattern (remove CanvasMsg wrapper and use the new sender method).
- WebGLCommands are the same ones as before (moved from webrender_api). So those lines are already reviewed.
- See WebGL traits in [components/canvas_traits/webgl.rs](https://github.com/servo/servo/pull/17891/files#diff-8701045d01505418701d0631d4d45562)
- See WebGLThread and WR External Image bridge in [components/canvas/webgl_thread.rs](https://github.com/servo/servo/pull/17891/files#diff-281554879f39a2a041f7a69d442a5d2e)
- The implementation submitted in this PR creates a single `WebGLThread` for all ScriptThread/Pipelines. See that in [components/canvas/webgl_mode/inprocess.rs](https://github.com/servo/servo/pull/17891/files#diff-250070c6c5a38c7f9fa0f5b3c101f68b)

The conformance tests will help to guarantee that we don't miss anything.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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1 files changed, 13 insertions, 16 deletions

diff --git a/components/script/dom/webglbuffer.rs b/components/script/dom/webglbuffer.rs
index 448956a9b90..96db4466d56 100644
--- a/components/script/dom/webglbuffer.rs
+++ b/components/script/dom/webglbuffer.rs
@@ -3,7 +3,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
-use canvas_traits::CanvasMsg;
+use canvas_traits::webgl::{WebGLBufferId, WebGLCommand, WebGLError, WebGLMsgSender, WebGLResult, WebGLVertexArrayId};
+use canvas_traits::webgl::webgl_channel;
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::WebGLBufferBinding;
 use dom::bindings::js::Root;
@@ -11,11 +12,9 @@ use dom::bindings::reflector::reflect_dom_object;
 use dom::webglobject::WebGLObject;
 use dom::window::Window;
 use dom_struct::dom_struct;
-use ipc_channel::ipc::IpcSender;
 use std::cell::Cell;
 use std::collections::HashSet;
-use webrender_api;
-use webrender_api::{WebGLBufferId, WebGLCommand, WebGLError, WebGLResult, WebGLVertexArrayId};
+
 
 #[dom_struct]
 pub struct WebGLBuffer {
@@ -29,11 +28,11 @@ pub struct WebGLBuffer {
     vao_references: DOMRefCell<Option<HashSet<WebGLVertexArrayId>>>,
     pending_delete: Cell<bool>,
     #[ignore_heap_size_of = "Defined in ipc-channel"]
-    renderer: IpcSender<CanvasMsg>,
+    renderer: WebGLMsgSender,
 }
 
 impl WebGLBuffer {
-    fn new_inherited(renderer: IpcSender<CanvasMsg>,
+    fn new_inherited(renderer: WebGLMsgSender,
                      id: WebGLBufferId)
                      -> WebGLBuffer {
         WebGLBuffer {
@@ -48,17 +47,17 @@ impl WebGLBuffer {
         }
     }
 
-    pub fn maybe_new(window: &Window, renderer: IpcSender<CanvasMsg>)
+    pub fn maybe_new(window: &Window, renderer: WebGLMsgSender)
                      -> Option<Root<WebGLBuffer>> {
-        let (sender, receiver) = webrender_api::channel::msg_channel().unwrap();
-        renderer.send(CanvasMsg::WebGL(WebGLCommand::CreateBuffer(sender))).unwrap();
+        let (sender, receiver) = webgl_channel().unwrap();
+        renderer.send(WebGLCommand::CreateBuffer(sender)).unwrap();
 
         let result = receiver.recv().unwrap();
         result.map(|buffer_id| WebGLBuffer::new(window, renderer, buffer_id))
     }
 
     pub fn new(window: &Window,
-               renderer: IpcSender<CanvasMsg>,
+               renderer: WebGLMsgSender,
                id: WebGLBufferId)
               -> Root<WebGLBuffer> {
         reflect_dom_object(box WebGLBuffer::new_inherited(renderer, id),
@@ -81,7 +80,7 @@ impl WebGLBuffer {
         } else {
             self.target.set(Some(target));
         }
-        let msg = CanvasMsg::WebGL(WebGLCommand::BindBuffer(target, Some(self.id)));
+        let msg = WebGLCommand::BindBuffer(target, Some(self.id));
         self.renderer.send(msg).unwrap();
 
         Ok(())
@@ -94,9 +93,7 @@ impl WebGLBuffer {
             }
         }
         self.capacity.set(data.len());
-        self.renderer
-            .send(CanvasMsg::WebGL(WebGLCommand::BufferData(target, data.to_vec(), usage)))
-            .unwrap();
+        self.renderer.send(WebGLCommand::BufferData(target, data.to_vec(), usage)).unwrap();
 
         Ok(())
     }
@@ -108,7 +105,7 @@ impl WebGLBuffer {
     pub fn delete(&self) {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
-            let _ = self.renderer.send(CanvasMsg::WebGL(WebGLCommand::DeleteBuffer(self.id)));
+            let _ = self.renderer.send(WebGLCommand::DeleteBuffer(self.id));
         }
     }
 
@@ -144,7 +141,7 @@ impl WebGLBuffer {
         if let Some(ref mut vao_refs) = *self.vao_references.borrow_mut() {
             if vao_refs.take(&id).is_some() && self.pending_delete.get() {
                 // WebGL spec: The deleted buffers should no longer be valid when the VAOs are deleted
-                let _ = self.renderer.send(CanvasMsg::WebGL(WebGLCommand::DeleteBuffer(self.id)));
+                let _ = self.renderer.send(WebGLCommand::DeleteBuffer(self.id));
                 self.is_deleted.set(true);
             }
         }