[metal] Use raw-window-metal to do layer creation

This uses observers internally, which fixes resizing when using Wgpu
together with an auto-layout NSView.

Though it probably won't matter much, it's also more reliable to update
the scale factor this way, rather than haphazardly in `configure`.

Author: madsmtm

.deny.toml

@@ -16,6 +16,9 @@ skip-tree = [
     { name = "bit-vec", version = "0.6.3" },
     { name = "capacity_builder", version = "0.1.3" },
     { name = "itertools", version = "0.10.5" },
+
+    # Winit 0.30 uses an older objc2
+    { name = "objc2-foundation", version = "0.2" },
 ]
 skip = [
     # Strum uses an old version

Cargo.lock

@@ -161,6 +161,7 @@ metal = "0.31.0"
 block = "0.1"
 core-graphics-types = "0.1"
 objc = "0.2.5"
+raw-window-metal = "1.0"
 
 # Vulkan dependencies
 android_system_properties = "0.1.1"

Cargo.toml

@@ -59,7 +59,7 @@ unexpected_cfgs = { level = "warn", check-cfg = [
 # exclude the Vulkan backend on MacOS unless a separate feature `vulkan-portability` is enabled. In response
 # to these features, it enables features of platform specific crates. For example, the `vulkan` feature in wgpu-core
 # enables the `vulkan` feature in `wgpu-core-deps-windows-linux-android` which in turn enables the
-# `vulkan` feature in `wgpu-hal` _only_ on those platforms. If you enable the `vulkan-portability` feature, it 
+# `vulkan` feature in `wgpu-hal` _only_ on those platforms. If you enable the `vulkan-portability` feature, it
 # will enable the `vulkan` feature in `wgpu-core-deps-apple`. The only way to do this is unfortunately to have
 # a separate crate for each platform category that participates in the feature unification.
 #
@@ -82,6 +82,7 @@ metal = [
     "dep:metal",
     "dep:objc",
     "dep:profiling",
+    "dep:raw-window-metal",
 ]
 vulkan = [
     "naga/spv-out",
@@ -96,6 +97,7 @@ vulkan = [
     "dep:log",
     "dep:ordered-float",
     "dep:profiling",
+    "dep:raw-window-metal",
     "dep:smallvec",
     "dep:windows",
     "windows/Win32",
@@ -112,6 +114,7 @@ gles = [
     "dep:libloading",
     "dep:log",
     "dep:ndk-sys",
+    "dep:objc",
     "dep:profiling",
     "dep:wasm-bindgen",
     "dep:web-sys",
@@ -274,6 +277,9 @@ core-graphics-types = { workspace = true, optional = true }
 metal = { workspace = true, optional = true }
 objc = { workspace = true, optional = true }
 
+# backend: Metal + Vulkan
+raw-window-metal = { workspace = true, optional = true }
+
 #########################
 ### Platform: Android ###
 #########################