Switch from ndk-glue to raw-window-handle crate

`winit` provides a `raw-window-handle` specifically for crates to
process window pointers/references in a crate-agnostic way.  `glutin`
can use it too, to get rid of its `ndk-glue` dependency which otherwise
has a hard versioning dependency  as it should be updated in sync with
`winit`.

Over time this should be worked into the other backends, in turn
removing `winit` from the `new_windowed()` function signature and
replacing it with `impl HasRawWindowHandle` or `dyn HasRawWindowHandle`.
This will also allow Android users to pass generic `Surface`s (first
converted to a so-called `NativeWindow` in the NDK through [#272], then
passed as `RawWindowHandle` thanks to [#274]) created in Java / Kotlin /
Flutter to render to individual UI elements instead of the entire screen
with a `NativeActivity` (`ndk-glue`).  It'll in turn make the code more
generic, too, as `raw-window-handle` has a variant for every platform /
windowing system currently supported by glutin.

[#272]: rust-mobile/ndk#272
[#274]: rust-mobile/ndk#274

CHANGELOG.md

@@ -5,7 +5,7 @@
 - Return an `Err` instead of panicking when surfaceless GLX context creation fails on Linux.
 - Fix compilation on Android:
   - Switch from `StaticStructGenerator` to `StructGenerator` to dynamically load symbols.
-  - Replace `android_glue` dependency with `ndk-glue`, and remove broken lifecycle event handling.
+  - Replace `android_glue` dependency with `raw-window-handle`, and remove broken lifecycle event handling.
   - Glutin can now be used on Android, however, the application must ensure it only creates the `Context` following a winit `Event::Resumed` event, and destroys the `Context` in response to a `Event::Suspended` event.
 
 # Version 0.28.0 (2021-12-02)

glutin/Cargo.toml

@@ -27,8 +27,8 @@ winit = { version = "0.26", default-features = false }
 [target.'cfg(target_os = "android")'.dependencies]
 glutin_egl_sys = { version = "0.1.5", path = "../glutin_egl_sys" }
 libloading = "0.7"
-ndk-glue = "0.5" # Keep in sync with winit
 parking_lot = "0.11"
+raw-window-handle = "0.4"
 
 [target.'cfg(target_os = "emscripten")'.dependencies]
 glutin_emscripten_sys = { version = "0.1.1", path = "../glutin_emscripten_sys" }

glutin/src/api/android/mod.rs

@@ -6,6 +6,7 @@ use crate::{Api, ContextError, GlAttributes, PixelFormat, PixelFormatRequirement
 
 use glutin_egl_sys as ffi;
 use parking_lot::Mutex;
+use raw_window_handle::{AndroidNdkHandle, HasRawWindowHandle, RawWindowHandle};
 use winit;
 use winit::dpi;
 use winit::event_loop::EventLoopWindowTarget;
@@ -32,15 +33,20 @@ impl Context {
     ) -> Result<(winit::window::Window, Self), CreationError> {
         let win = wb.build(el)?;
         let gl_attr = gl_attr.clone().map_sharing(|c| &c.0.egl_context);
-        let nwin = ndk_glue::native_window();
         let nwin =
-            nwin.as_ref().ok_or_else(|| OsError("Android's native window is null".to_string()))?;
+            if let RawWindowHandle::AndroidNdk(AndroidNdkHandle { a_native_window, .. }) =
+                win.raw_window_handle()
+            {
+                a_native_window
+            } else {
+                return Err(OsError("raw_window_handle() is not for Android".to_string()));
+            };
         let native_display = NativeDisplay::Android;
         let egl_context =
             EglContext::new(pf_reqs, &gl_attr, native_display, EglSurfaceType::Window, |c, _| {
                 Ok(c[0])
             })
-            .and_then(|p| p.finish(nwin.ptr().as_ptr() as *const _))?;
+            .and_then(|p| p.finish(nwin))?;
         let ctx = Arc::new(AndroidContext { egl_context, stopped: Some(Mutex::new(false)) });
 
         let context = Context(ctx.clone());