Add multithreaded fake encoder and corresponding FlexFEC VideoSendStreamTest.

webrtc/test/fake_encoder.h

 /*
  *  Copyright (c) 2013 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_TEST_FAKE_ENCODER_H_
 #define WEBRTC_TEST_FAKE_ENCODER_H_
 
 #include <vector>
 
 #include "webrtc/base/criticalsection.h"
+#include "webrtc/base/task_queue.h"
 #include "webrtc/common_types.h"
 #include "webrtc/system_wrappers/include/clock.h"
 #include "webrtc/video_encoder.h"
 
 namespace webrtc {
 namespace test {
 
 class FakeEncoder : public VideoEncoder {
  public:
   explicit FakeEncoder(Clock* clock);
@@ skipping 52 matching lines @@
 
   void SetDelay(int delay_ms);
   int32_t Encode(const VideoFrame& input_image,
                  const CodecSpecificInfo* codec_specific_info,
                  const std::vector<FrameType>* frame_types) override;
 
  private:
   rtc::CriticalSection lock_;
   int delay_ms_ GUARDED_BY(&lock_);
 };
+
+// This class implements a multi-threaded fake encoder by posting
+// FakeH264Encoder::Encode(.) tasks to |queue1_| and |queue2_|, in an
+// alternating fashion.
+class MultiThreadedFakeH264Encoder : public test::FakeH264Encoder {
+ public:
+  MultiThreadedFakeH264Encoder(Clock* clock);
+  virtual ~MultiThreadedFakeH264Encoder() override;
+
+  int32_t Encode(const VideoFrame& input_image,
+                 const CodecSpecificInfo* codec_specific_info,
+                 const std::vector<FrameType>* frame_types) override;
+
+  int32_t EncodeCallback(const VideoFrame& input_image,
+                         const CodecSpecificInfo* codec_specific_info,
+                         const std::vector<FrameType>* frame_types);
+
+ protected:
+  class EncodeTask;
+
+  int current_queue_;
+  rtc::TaskQueue queue1_;
+  rtc::TaskQueue queue2_;
+};
+
 }  // namespace test
 }  // namespace webrtc
 
 #endif  // WEBRTC_TEST_FAKE_ENCODER_H_