Auto merge of #26036 - gterzian:add_ipc_router_shutdown, r=Manishearth

Add ipc router shutdown

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Explicitly shutting down IPC router as part of shutdown, for contexts see https://github.com/servo/servo/pull/25685#pullrequestreview-364604068

Note that the call to `shutdown` is idempotent, so it shouldn't matter whether the call in the constellation and the script-thread are actually on the same `ROUTER` in single-process mode...

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- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #___ (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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Cargo.lock

@@ -2755,9 +2755,9 @@ dependencies = [
 
 [[package]]
 name = "ipc-channel"
-version = "0.14.0"
+version = "0.14.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "55162cbe44dacbc0b4a66d1067c885a9d5975f068a432801bba0493e1ece7a51"
+checksum = "3698b8affd5656032a074a7d40b3c2a29b71971f3e1ff6042b9d40724e20d97c"
 dependencies = [
  "bincode",
  "crossbeam-channel",

components/constellation/constellation.rs

@@ -2833,6 +2833,9 @@ where
         debug!("Asking compositor to complete shutdown.");
         self.compositor_proxy
             .send(ToCompositorMsg::ShutdownComplete);
+
+        debug!("Shutting-down IPC router thread in constellation.");
+        ROUTER.shutdown();
     }
 
     fn handle_pipeline_exited(&mut self, pipeline_id: PipelineId) {

components/script/script_thread.rs

@@ -145,6 +145,7 @@ use script_traits::{ScriptToConstellationChan, TimerSchedulerMsg};
 use script_traits::{TouchEventType, TouchId, UntrustedNodeAddress, WheelDelta};
 use script_traits::{UpdatePipelineIdReason, WebrenderIpcSender, WindowSizeData, WindowSizeType};
 use servo_atoms::Atom;
+use servo_config::opts;
 use servo_url::{ImmutableOrigin, MutableOrigin, ServoUrl};
 use std::borrow::Cow;
 use std::cell::Cell;
@@ -2908,6 +2909,12 @@ impl ScriptThread {
             .as_ref()
             .map(|bhm| bhm.unregister());
 
+        // If we're in multiprocess mode, shut-down the IPC router for this process.
+        if opts::multiprocess() {
+            debug!("Exiting IPC router thread in script thread.");
+            ROUTER.shutdown();
+        }
+
         debug!("Exited script thread.");
     }