Remove all NativeSwapChain*

These were helpers to avoid the need for users of implementation-based
swapchains to implement them themselves. They are no longer used and can
be removed.

Also removes SwapChainuUtils.h that's no longer used.

Bug: dawn:269
Change-Id: I3c563edaf107e9ce04f708e8bacae9d231b0f40d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/126421
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Loko Kung <lokokung@google.com>

include/dawn/native/OpenGLBackend.h

@@ -17,7 +17,6 @@
 
 typedef void* EGLImage;
 
-#include "dawn/dawn_wsi.h"
 #include "dawn/native/DawnNative.h"
 
 namespace dawn::native::opengl {
@@ -33,13 +32,6 @@ struct DAWN_NATIVE_EXPORT AdapterDiscoveryOptionsES : public AdapterDiscoveryOpt
     AdapterDiscoveryOptionsES();
 };
 
-using PresentCallback = void (*)(void*);
-DAWN_NATIVE_EXPORT DawnSwapChainImplementation CreateNativeSwapChainImpl(WGPUDevice device,
-                                                                         PresentCallback present,
-                                                                         void* presentUserdata);
-DAWN_NATIVE_EXPORT WGPUTextureFormat
-GetNativeSwapChainPreferredFormat(const DawnSwapChainImplementation* swapChain);
-
 struct DAWN_NATIVE_EXPORT ExternalImageDescriptorEGLImage : ExternalImageDescriptor {
   public:
     ExternalImageDescriptorEGLImage();