Revert of Reuse allocated encoders in SimulcastEncoderAdapter.

webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.h

 /*
  *  Copyright (c) 2014 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_CODECS_VP8_SIMULCAST_ENCODER_ADAPTER_H_
 #define WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_SIMULCAST_ENCODER_ADAPTER_H_
 
 #include <memory>
-#include <stack>
 #include <string>
-#include <utility>
 #include <vector>
 
-#include "webrtc/base/atomicops.h"
-#include "webrtc/base/sequenced_task_checker.h"
 #include "webrtc/modules/video_coding/codecs/vp8/include/vp8.h"
 
 namespace webrtc {
 
 class SimulcastRateAllocator;
 
-// TODO(brandtr): Remove this class and replace its use with a
-// WebRtcVideoEncoderFactory.
 class VideoEncoderFactory {
  public:
   virtual VideoEncoder* Create() = 0;
   virtual void Destroy(VideoEncoder* encoder) = 0;
   virtual ~VideoEncoderFactory() {}
 };
 
 // SimulcastEncoderAdapter implements simulcast support by creating multiple
 // webrtc::VideoEncoder instances with the given VideoEncoderFactory.
-// The object is created and destroyed on the worker thread, but all public
-// interfaces should be called from the encoder task queue.
+// All the public interfaces are expected to be called from the same thread,
+// e.g the encoder thread.
 class SimulcastEncoderAdapter : public VP8Encoder {
  public:
-  // TODO(brandtr): Make it clear that the ownership of |factory| is transferred
-  // by only accepting a std::unique_ptr<VideoEncoderFactory> here.
   explicit SimulcastEncoderAdapter(VideoEncoderFactory* factory);
   virtual ~SimulcastEncoderAdapter();
 
-  // Implements VideoEncoder.
+  // Implements VideoEncoder
   int Release() override;
   int InitEncode(const VideoCodec* inst,
                  int number_of_cores,
                  size_t max_payload_size) override;
   int Encode(const VideoFrame& input_image,
              const CodecSpecificInfo* codec_specific_info,
              const std::vector<FrameType>* frame_types) override;
   int RegisterEncodeCompleteCallback(EncodedImageCallback* callback) override;
   int SetChannelParameters(uint32_t packet_loss, int64_t rtt) override;
   int SetRateAllocation(const BitrateAllocation& bitrate,
                         uint32_t new_framerate) override;
 
   // Eventual handler for the contained encoders' EncodedImageCallbacks, but
   // called from an internal helper that also knows the correct stream
   // index.
   EncodedImageCallback::Result OnEncodedImage(
       size_t stream_idx,
       const EncodedImage& encoded_image,
       const CodecSpecificInfo* codec_specific_info,
       const RTPFragmentationHeader* fragmentation);
 
   VideoEncoder::ScalingSettings GetScalingSettings() const override;
 
   bool SupportsNativeHandle() const override;
   const char* ImplementationName() const override;
 
  private:
   struct StreamInfo {
+    StreamInfo()
+        : encoder(NULL),
+          callback(NULL),
+          width(0),
+          height(0),
+          key_frame_request(false),
+          send_stream(true) {}
     StreamInfo(VideoEncoder* encoder,
-               std::unique_ptr<EncodedImageCallback> callback,
+               EncodedImageCallback* callback,
                uint16_t width,
                uint16_t height,
                bool send_stream)
         : encoder(encoder),
-          callback(std::move(callback)),
+          callback(callback),
           width(width),
           height(height),
           key_frame_request(false),
           send_stream(send_stream) {}
-    // Deleted by SimulcastEncoderAdapter::DestroyStoredEncoders().
+    // Deleted by SimulcastEncoderAdapter::Release().
     VideoEncoder* encoder;
-    std::unique_ptr<EncodedImageCallback> callback;
+    EncodedImageCallback* callback;
     uint16_t width;
     uint16_t height;
     bool key_frame_request;
     bool send_stream;
   };
 
-  // Populate the codec settings for each simulcast stream.
-  static void PopulateStreamCodec(const webrtc::VideoCodec& inst,
-                                  int stream_index,
-                                  uint32_t start_bitrate_kbps,
-                                  bool highest_resolution_stream,
-                                  webrtc::VideoCodec* stream_codec);
+  // Populate the codec settings for each stream.
+  void PopulateStreamCodec(const webrtc::VideoCodec* inst,
+                           int stream_index,
+                           uint32_t start_bitrate_kbps,
+                           bool highest_resolution_stream,
+                           webrtc::VideoCodec* stream_codec);
 
   bool Initialized() const;
 
-  void DestroyStoredEncoders();
-
-  volatile int inited_;  // Accessed atomically.
-  const std::unique_ptr<VideoEncoderFactory> factory_;
+  std::unique_ptr<VideoEncoderFactory> factory_;
   VideoCodec codec_;
   std::vector<StreamInfo> streaminfos_;
   EncodedImageCallback* encoded_complete_callback_;
   std::string implementation_name_;
-
-  // Used for checking the single-threaded access of the encoder interface.
-  rtc::SequencedTaskChecker encoder_queue_;
-
-  // Store encoders in between calls to Release and InitEncode, so they don't
-  // have to be recreated. Remaining encoders are destroyed by the destructor.
-  std::stack<VideoEncoder*> stored_encoders_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_SIMULCAST_ENCODER_ADAPTER_H_