message: Make some DecisionLogic functions virtual.
  Cr-Commit-Position: refs/heads/master@{#29684}
diff: @@ -99,7 +99,7 @@ class DecisionLogic : public NetEqController {
  }
  bool PeakFound() const override { return delay_manager_->PeakFound(); }
  - virtual int GetFilteredBufferLevel() const override {
  + int GetFilteredBufferLevel() const override {
  return buffer_level_filter_.filtered_current_level();
  }
  @@ -126,22 +126,23 @@ class DecisionLogic : public NetEqController {
  // Returns the operation given that the next available packet is a comfort
  // noise payload (RFC 3389 only, not codec-internal).
  - NetEq::Operation CngOperation(NetEq::Mode prev_mode,
  + virtual NetEq::Operation CngOperation(NetEq::Mode prev_mode,
  uint32_t target_timestamp,
  uint32_t available_timestamp,
  size_t generated_noise_samples);
  // Returns the operation given that no packets are available (except maybe
  // a DTMF event, flagged by setting |play_dtmf| true).
  - NetEq::Operation NoPacket(bool play_dtmf);
  + virtual NetEq::Operation NoPacket(bool play_dtmf);
  // Returns the operation to do given that the expected packet is available.
  - NetEq::Operation ExpectedPacketAvailable(NetEq::Mode prev_mode,
  + virtual NetEq::Operation ExpectedPacketAvailable(NetEq::Mode prev_mode,
  bool play_dtmf);
  // Returns the operation to do given that the expected packet is not
  // available, but a packet further into the future is at hand.
  - NetEq::Operation FuturePacketAvailable(size_t decoder_frame_length,
  + virtual NetEq::Operation FuturePacketAvailable(
  + size_t decoder_frame_length,
  NetEq::Mode prev_mode,
  uint32_t target_timestamp,
  uint32_t available_timestamp,
  