Mus: Delete unused Mandoline Surfaces code

components/mus/public/cpp/surfaces/custom_surface_converter.h

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef COMPONENTS_MUS_PUBLIC_CPP_SURFACES_CUSTOM_SURFACE_CONVERTER_H_
-#define COMPONENTS_MUS_PUBLIC_CPP_SURFACES_CUSTOM_SURFACE_CONVERTER_H_
-
-#include "cc/ipc/quads.mojom.h"
-#include "components/mus/public/interfaces/compositor_frame.mojom.h"
-
-namespace cc {
-class CompositorFrameMetadata;
-class RenderPass;
-class SharedQuadState;
-}  // namespace cc
-
-namespace mojo {
-
-// Classes that inherit from this converter can override the default behavior
-// for converting a mojo::SurfaceDrawState to something cc understands.
-class CustomSurfaceConverter {
- public:
-  virtual bool ConvertSurfaceDrawQuad(
-      const cc::mojom::DrawQuadPtr& input,
-      const cc::CompositorFrameMetadata& metadata,
-      cc::SharedQuadState* sqs,
-      cc::RenderPass* render_pass) = 0;
-
- protected:
-  virtual ~CustomSurfaceConverter() {}
-};
-
-} // namespace mojo
-
-#endif  // COMPONENTS_MUS_PUBLIC_CPP_SURFACES_CUSTOM_SURFACE_CONVERTER_H_