[Metal] Add a way to create a device and queue from raw resources in wgpu-hal

CHANGELOG.md

@@ -269,6 +269,9 @@ By @jimblandy in [#3254](https://github.com/gfx-rs/wgpu/pull/3254).
 - Add `MULTISAMPLE_X2`, `MULTISAMPLE_X4` and `MULTISAMPLE_X8` to `TextureFormatFeatureFlags`. By @39ali in [3140](https://github.com/gfx-rs/wgpu/pull/3140)
 - Sync `TextureFormat.describe` with the spec. By @teoxoy in [3312](https://github.com/gfx-rs/wgpu/pull/3312)
 
+#### Metal
+- Add a way to create `Device` and `Queue` from raw Metal resources in wgpu-hal. By @AdrianEddy in [#3338](https://github.com/gfx-rs/wgpu/pull/3338)
+
 ### Bug Fixes
 
 #### General

wgpu-hal/src/metal/device.rs

@@ -219,6 +219,13 @@ impl super::Device {
         }
     }
 
+    pub unsafe fn device_from_raw(raw: mtl::Device, features: wgt::Features) -> super::Device {
+        super::Device {
+            shared: Arc::new(super::AdapterShared::new(raw)),
+            features,
+        }
+    }
+
     pub fn raw_device(&self) -> &Mutex<mtl::Device> {
         &self.shared.device
     }

wgpu-hal/src/metal/mod.rs

@@ -286,6 +286,13 @@ pub struct Queue {
 unsafe impl Send for Queue {}
 unsafe impl Sync for Queue {}
 
+impl Queue {
+    pub unsafe fn queue_from_raw(raw: mtl::CommandQueue) -> Self {
+        Self {
+            raw: Arc::new(Mutex::new(raw)),
+        }
+    }
+}
 pub struct Device {
     shared: Arc<AdapterShared>,
     features: wgt::Features,