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/software_output_device_proxy.h

@@ -0,0 +1,52 @@
+#ifndef CEF_LIBCEF_BROWSER_OSR_SOFTWARE_OUTPUT_DEVICE_PROXY_H_
+#define CEF_LIBCEF_BROWSER_OSR_SOFTWARE_OUTPUT_DEVICE_PROXY_H_
+
+#include "base/memory/shared_memory_mapping.h"
+#include "base/threading/thread_checker.h"
+#include "components/viz/service/display/software_output_device.h"
+#include "components/viz/service/viz_service_export.h"
+#include "services/viz/privileged/interfaces/compositing/display_private.mojom.h"
+#include "services/viz/privileged/interfaces/compositing/layered_window_updater.mojom.h"
+
+namespace viz {
+
+// SoftwareOutputDevice implementation that draws indirectly. An
+// implementation of mojom::LayeredWindowUpdater in the browser process
+// handles the actual drawing. Pixel backing is in SharedMemory so no copying
+// between processes is required.
+class VIZ_SERVICE_EXPORT SoftwareOutputDeviceProxy
+    : public SoftwareOutputDevice {
+ public:
+  explicit SoftwareOutputDeviceProxy(
+      mojom::LayeredWindowUpdaterPtr layered_window_updater);
+  ~SoftwareOutputDeviceProxy() override;
+
+  // SoftwareOutputDevice implementation.
+  void OnSwapBuffers(SwapBuffersCallback swap_ack_callback) override;
+
+  // SoftwareOutputDeviceBase implementation.
+  void Resize(const gfx::Size& viewport_pixel_size,
+              float scale_factor) override;
+  SkCanvas* BeginPaint(const gfx::Rect& damage_rect) override;
+  void EndPaint() override;
+
+ private:
+  // Runs |swap_ack_callback_| after draw has happened.
+  void DrawAck();
+
+  mojom::LayeredWindowUpdaterPtr layered_window_updater_;
+
+  std::unique_ptr<SkCanvas> canvas_;
+  bool waiting_on_draw_ack_ = false;
+  bool in_paint_ = false;
+  base::OnceClosure swap_ack_callback_;
+  base::WritableSharedMemoryMapping shm_;
+
+  THREAD_CHECKER(thread_checker_);
+
+  DISALLOW_COPY_AND_ASSIGN(SoftwareOutputDeviceProxy);
+};
+
+}  // namespace viz
+
+#endif  // CEF_LIBCEF_BROWSER_OSR_SOFTWARE_OUTPUT_DEVICE_PROXY_H_