WebRTC: Add compability header for video_coding refactoring.

It turns out there were downstream use of the encoded_frame.h header
that was moved in https://codereview.webrtc.org/1417283007/.
Add a copy of it in the old location to allow a seamless transition.

BUG=webrtc:5095
TBR=stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1447163006 .

Cr-Commit-Position: refs/heads/master@{#10696}
diff --git a/webrtc/modules/video_coding/main/source/encoded_frame.h b/webrtc/modules/video_coding/main/source/encoded_frame.h
new file mode 100644
index 0000000..a058655
--- /dev/null
+++ b/webrtc/modules/video_coding/main/source/encoded_frame.h
@@ -0,0 +1,129 @@
+/*
+ *  Copyright (c) 2011 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_MODULES_VIDEO_CODING_ENCODED_FRAME_H_
+#define WEBRTC_MODULES_VIDEO_CODING_ENCODED_FRAME_H_
+
+#pragma message("WARNING: video_coding/main/source is DEPRECATED; use video_coding/ instead.")
+
+#include <vector>
+
+#include "webrtc/common_types.h"
+#include "webrtc/common_video/include/video_image.h"
+#include "webrtc/modules/include/module_common_types.h"
+#include "webrtc/modules/video_coding/include/video_codec_interface.h"
+#include "webrtc/modules/video_coding/include/video_coding_defines.h"
+
+namespace webrtc
+{
+
+class VCMEncodedFrame : protected EncodedImage
+{
+public:
+    VCMEncodedFrame();
+    VCMEncodedFrame(const webrtc::EncodedImage& rhs);
+    VCMEncodedFrame(const VCMEncodedFrame& rhs);
+
+    ~VCMEncodedFrame();
+    /**
+    *   Delete VideoFrame and resets members to zero
+    */
+    void Free();
+    /**
+    *   Set render time in milliseconds
+    */
+    void SetRenderTime(const int64_t renderTimeMs) {_renderTimeMs = renderTimeMs;}
+
+    /**
+    *   Set the encoded frame size
+    */
+    void SetEncodedSize(uint32_t width, uint32_t height)
+                       { _encodedWidth  = width; _encodedHeight = height; }
+    /**
+    *   Get the encoded image
+    */
+    const webrtc::EncodedImage& EncodedImage() const
+                       { return static_cast<const webrtc::EncodedImage&>(*this); }
+    /**
+    *   Get pointer to frame buffer
+    */
+    const uint8_t* Buffer() const {return _buffer;}
+    /**
+    *   Get frame length
+    */
+    size_t Length() const {return _length;}
+    /**
+    *   Get frame timestamp (90kHz)
+    */
+    uint32_t TimeStamp() const {return _timeStamp;}
+    /**
+    *   Get render time in milliseconds
+    */
+    int64_t RenderTimeMs() const {return _renderTimeMs;}
+    /**
+    *   Get frame type
+    */
+    webrtc::FrameType FrameType() const { return _frameType; }
+    /**
+    *   Get frame rotation
+    */
+    VideoRotation rotation() const { return _rotation; }
+    /**
+    *   True if this frame is complete, false otherwise
+    */
+    bool Complete() const { return _completeFrame; }
+    /**
+    *   True if there's a frame missing before this frame
+    */
+    bool MissingFrame() const { return _missingFrame; }
+    /**
+    *   Payload type of the encoded payload
+    */
+    uint8_t PayloadType() const { return _payloadType; }
+    /**
+    *   Get codec specific info.
+    *   The returned pointer is only valid as long as the VCMEncodedFrame
+    *   is valid. Also, VCMEncodedFrame owns the pointer and will delete
+    *   the object.
+    */
+    const CodecSpecificInfo* CodecSpecific() const {return &_codecSpecificInfo;}
+
+    const RTPFragmentationHeader* FragmentationHeader() const;
+
+protected:
+    /**
+    * Verifies that current allocated buffer size is larger than or equal to the input size.
+    * If the current buffer size is smaller, a new allocation is made and the old buffer data
+    * is copied to the new buffer.
+    * Buffer size is updated to minimumSize.
+    */
+    void VerifyAndAllocate(size_t minimumSize);
+
+    void Reset();
+
+    void CopyCodecSpecific(const RTPVideoHeader* header);
+
+    int64_t                 _renderTimeMs;
+    uint8_t                 _payloadType;
+    bool                          _missingFrame;
+    CodecSpecificInfo             _codecSpecificInfo;
+    webrtc::VideoCodecType        _codec;
+    RTPFragmentationHeader        _fragmentation;
+    VideoRotation                 _rotation;
+
+    // Video rotation is only set along with the last packet for each frame
+    // (same as marker bit). This |_rotation_set| is only for debugging purpose
+    // to ensure we don't set it twice for a frame.
+    bool                          _rotation_set;
+};
+
+}  // namespace webrtc
+
+#endif // WEBRTC_MODULES_VIDEO_CODING_ENCODED_FRAME_H_