Add raw sources and sinks to cscore (#1670)

In some cases, we don't want the cv requirement to get an image, for instance interop with other versions of opencv

This enables getting a raw image, and handling conversions from the user side.

cscore/src/main/native/cpp/RawSourceImpl.h

@@ -0,0 +1,41 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2016-2019 FIRST. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef CSCORE_RAWSOURCEIMPL_H_
+#define CSCORE_RAWSOURCEIMPL_H_
+
+#include <atomic>
+#include <functional>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <wpi/ArrayRef.h>
+#include <wpi/Twine.h>
+
+#include "ConfigurableSourceImpl.h"
+#include "SourceImpl.h"
+#include "cscore_raw.h"
+
+namespace cs {
+
+class RawSourceImpl : public ConfigurableSourceImpl {
+ public:
+  RawSourceImpl(const wpi::Twine& name, wpi::Logger& logger, Notifier& notifier,
+                Telemetry& telemetry, const VideoMode& mode);
+  ~RawSourceImpl() override;
+
+  // Raw-specific functions
+  void PutFrame(const CS_RawFrame& image);
+
+ private:
+  std::atomic_bool m_connected{true};
+};
+
+}  // namespace cs
+
+#endif  // CSCORE_RAWSOURCEIMPL_H_