Prepare for injectable SW decoders

webrtc/media/engine/scopedvideodecoder.h

Index: webrtc/media/engine/scopedvideodecoder.h
diff --git a/webrtc/media/engine/scopedvideodecoder.h b/webrtc/media/engine/scopedvideodecoder.h
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+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MEDIA_ENGINE_SCOPEDVIDEODECODER_H_
+#define WEBRTC_MEDIA_ENGINE_SCOPEDVIDEODECODER_H_
+
+#include <memory>
+
+#include "webrtc/media/engine/webrtcvideodecoderfactory.h"
+
+namespace cricket {
+
+// Helper function that creates a webrtc::VideoDecoder held by an
+// std::unique_ptr instead of having to be deleted through
+// WebRtcVideoDecoderFactory::DestroyVideoDecoder. The factory passed in must
+// outlive the returned encoder.
+// TODO(andersc): This helper function will be deleted once
+// cricket::WebRtcVideoDecoderFactory is deprecated, see
+// https://bugs.chromium.org/p/webrtc/issues/detail?id=7925 for more info.
+std::unique_ptr<webrtc::VideoDecoder> CreateScopedVideoDecoder(
+    cricket::WebRtcVideoDecoderFactory* factory,
+    webrtc::VideoCodecType type);
+std::unique_ptr<webrtc::VideoDecoder> CreateScopedVideoDecoder(
+    cricket::WebRtcVideoDecoderFactory* factory,
+    webrtc::VideoCodecType type,
+    VideoDecoderParams params);
+
+}  // namespace cricket
+
+#endif  // WEBRTC_MEDIA_ENGINE_SCOPEDVIDEODECODER_H_