Add initial Viz implementation for OSR (see issue #2575).

The old shared surface implementation has been removed and will need to be
re-implemented using the Viz code path.

libcef/browser/osr/host_display_client_osr.h

@@ -0,0 +1,42 @@
+// Copyright 2019 The Chromium Embedded Framework 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 CEF_LIBCEF_BROWSER_OSR_HOST_DISPLAY_CLIENT_OSR_H_
+#define CEF_LIBCEF_BROWSER_OSR_HOST_DISPLAY_CLIENT_OSR_H_
+
+#include <memory>
+
+#include "base/callback.h"
+#include "base/memory/shared_memory.h"
+#include "components/viz/host/host_display_client.h"
+#include "ui/gfx/native_widget_types.h"
+
+class CefLayeredWindowUpdaterOSR;
+class CefRenderWidgetHostViewOSR;
+
+class CefHostDisplayClientOSR : public viz::HostDisplayClient {
+ public:
+  CefHostDisplayClientOSR(CefRenderWidgetHostViewOSR* const view,
+                          gfx::AcceleratedWidget widget);
+  ~CefHostDisplayClientOSR() override;
+
+  void SetActive(bool active);
+  const void* GetPixelMemory() const;
+  gfx::Size GetPixelSize() const;
+
+ private:
+  // mojom::DisplayClient implementation.
+  void UseProxyOutputDevice(UseProxyOutputDeviceCallback callback) override;
+
+  void CreateLayeredWindowUpdater(
+      viz::mojom::LayeredWindowUpdaterRequest request) override;
+
+  CefRenderWidgetHostViewOSR* const view_;
+  std::unique_ptr<CefLayeredWindowUpdaterOSR> layered_window_updater_;
+  bool active_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(CefHostDisplayClientOSR);
+};
+
+#endif  // CEF_LIBCEF_BROWSER_OSR_HOST_DISPLAY_CLIENT_OSR_H_