Auto merge of #19547 - tigercosmos:b1, r=jdm

Send IPC receiver for canvas as part of CreateCanvasPaintThread message

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I am not sure if @jdm want this.
r? @jdm

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #19483(github issue number if applicable).

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

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components/canvas/canvas_paint_thread.rs

@@ -11,7 +11,7 @@ use azure::azure_hl::SurfacePattern;
 use canvas_traits::canvas::*;
 use cssparser::RGBA;
 use euclid::{Transform2D, Point2D, Vector2D, Rect, Size2D};
-use ipc_channel::ipc::{self, IpcSender};
+use ipc_channel::ipc::{self, IpcSender, IpcReceiver};
 use num_traits::ToPrimitive;
 use std::borrow::ToOwned;
 use std::mem;
@@ -118,9 +118,8 @@ impl<'a> CanvasPaintThread<'a> {
     /// communicate with it.
     pub fn start(size: Size2D<i32>,
                  webrender_api_sender: webrender_api::RenderApiSender,
-                 antialias: bool)
-                 -> IpcSender<CanvasMsg> {
-        let (sender, receiver) = ipc::channel::<CanvasMsg>().unwrap();
+                 antialias: bool,
+                 receiver: IpcReceiver<CanvasMsg>) {
         let antialias = if antialias {
             AntialiasMode::Default
         } else {
@@ -216,8 +215,6 @@ impl<'a> CanvasPaintThread<'a> {
                 }
             }
         }).expect("Thread spawning failed");
-
-        sender
     }
 
     fn save_context_state(&mut self) {