Make DeviceLostClosure.from_c mutate the closure before dropping it.

wgpu-core/src/device/mod.rs

@@ -294,14 +294,18 @@ impl DeviceLostClosure {
     ///
     /// - Both pointers must point to `'static` data, as the callback may happen at
     ///   an unspecified time.
-    pub unsafe fn from_c(closure: DeviceLostClosureC) -> Self {
+    pub unsafe fn from_c(mut closure: DeviceLostClosureC) -> Self {
         // Build an inner with the values from closure, ensuring that
         // inner.called is false.
         let inner = DeviceLostClosureC {
             callback: closure.callback,
             user_data: closure.user_data,
             called: false,
         };
+
+        // Mark the original closure as called, so we can safely drop it.
+        closure.called = true;
+
         Self {
             inner: DeviceLostClosureInner::C { inner },
         }