Request keyframes more frequently on stream start/decoding error.

webrtc/modules/video_coding/frame_buffer2_unittest.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
@@ skipping 149 matching lines @@
     frame->spatial_layer = spatial_layer;
     frame->timestamp = ts_ms * 90;
     frame->num_references = references.size();
     frame->inter_layer_predicted = inter_layer_predicted;
     for (size_t r = 0; r < references.size(); ++r)
       frame->references[r] = references[r];
 
     return buffer_.InsertFrame(std::move(frame));
   }
 
-  void ExtractFrame(int64_t max_wait_time = 0) {
+  void ExtractFrame(int64_t max_wait_time = 0, bool keyframe_required = false) {
     crit_.Enter();
     if (max_wait_time == 0) {
       std::unique_ptr<FrameObject> frame;
-      FrameBuffer::ReturnReason res = buffer_.NextFrame(0, &frame);
+      FrameBuffer::ReturnReason res =
+          buffer_.NextFrame(0, &frame, keyframe_required);
       if (res != FrameBuffer::ReturnReason::kStopped)
         frames_.emplace_back(std::move(frame));
       crit_.Leave();
     } else {
       max_wait_time_ = max_wait_time;
       trigger_extract_event_.Set();
       crit_.Leave();
       // Make sure |crit_| is aquired by |extract_thread_| before returning.
       crit_acquired_event_.Wait(rtc::Event::kForever);
     }
@@ skipping 348 matching lines @@
 }
 
 // TODO(philipel): implement more unittests related to invalid references.
 TEST_F(TestFrameBuffer2, InvalidReferences) {
   EXPECT_EQ(-1, InsertFrame(0, 0, 1000, false, 2));
   EXPECT_EQ(1, InsertFrame(1, 0, 2000, false));
   ExtractFrame();
   EXPECT_EQ(2, InsertFrame(2, 0, 3000, false, 1));
 }
 
+TEST_F(TestFrameBuffer2, KeyframeRequired) {
+  EXPECT_EQ(1, InsertFrame(1, 0, 1000, false));
+  EXPECT_EQ(2, InsertFrame(2, 0, 2000, false, 1));
+  EXPECT_EQ(3, InsertFrame(3, 0, 3000, false));
+  ExtractFrame();
+  ExtractFrame(0, true);
+  ExtractFrame();
+
+  CheckFrame(0, 1, 0);
+  CheckFrame(1, 3, 0);
+  CheckNoFrame(2);
+}
+
 }  // namespace video_coding
 }  // namespace webrtc