Don't reset encoder on max/min bitrate change.

- Don't reset encoder if max/min bitrate changed.
- Removed min/max bitrate DCHECKs from encoder wrappers.
- Reset encoder if start_bitrate changed. Only do this if encoding
  has not yet started.
- Updated ReconfigureBitratesSetsEncoderBitratesCorrectly test.
- Removed EncoderSetupPropagatesCommonEncoderConfigValues test since it
was a subset of ReconfigureBitratesSetsEncoderBitratesCorrectly.

Bug: webrtc:10773
Change-Id: Id9cbb2ea229232fd95967819e2a937b26948de9f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/144028
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28446}

modules/video_coding/codecs/h264/h264_encoder_impl.cc

@@ -337,19 +337,12 @@ void H264EncoderImpl::SetRates(const RateControlParameters& parameters) {
 
   if (parameters.bitrate.get_sum_bps() == 0) {
     // Encoder paused, turn off all encoding.
-    for (size_t i = 0; i < configurations_.size(); ++i)
+    for (size_t i = 0; i < configurations_.size(); ++i) {
       configurations_[i].SetStreamState(false);
+    }
     return;
   }
 
-  // At this point, bitrate allocation should already match codec settings.
-  if (codec_.maxBitrate > 0)
-    RTC_DCHECK_LE(parameters.bitrate.get_sum_kbps(), codec_.maxBitrate);
-  RTC_DCHECK_GE(parameters.bitrate.get_sum_kbps(), codec_.minBitrate);
-  if (codec_.numberOfSimulcastStreams > 0)
-    RTC_DCHECK_GE(parameters.bitrate.get_sum_kbps(),
-                  codec_.simulcastStream[0].minBitrate);
-
   codec_.maxFramerate = static_cast<uint32_t>(parameters.framerate_fps);
 
   size_t stream_idx = encoders_.size() - 1;