app,gpu: move errDeviceLost from package app to package gpu

The Vulkan backend can return device lost error from more than just
Present.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gpu/api.go

@@ -28,3 +28,7 @@ type Direct3D11 = driver.Direct3D11
 
 // Metal denotes the Apple Metal API.
 type Metal = driver.Metal
+
+// ErrDeviceLost is returned from GPU operations when the underlying GPU device
+// is lost and should be recreated.
+var ErrDeviceLost = driver.ErrDeviceLost

gpu/internal/driver/driver.go

@@ -54,6 +54,8 @@ type Device interface {
 	Release()
 }
 
+var ErrDeviceLost = errors.New("GPU device lost")
+
 type LoadDesc struct {
 	Action     LoadAction
 	ClearColor f32color.RGBA