Make FakeDecodeFromFile handle codec-internal CNG

webrtc/modules/audio_coding/neteq/tools/fake_decode_from_file.h

Index: webrtc/modules/audio_coding/neteq/tools/fake_decode_from_file.h
diff --git a/webrtc/modules/audio_coding/neteq/tools/fake_decode_from_file.h b/webrtc/modules/audio_coding/neteq/tools/fake_decode_from_file.h
index 2c51998261c3998baa85345f6fafcab173d865a6..69f9c82d3845a6a1569782cd9acaad43ef5ef7e4 100644
--- a/webrtc/modules/audio_coding/neteq/tools/fake_decode_from_file.h
+++ b/webrtc/modules/audio_coding/neteq/tools/fake_decode_from_file.h
@@ -50,11 +50,13 @@ class FakeDecodeFromFile : public AudioDecoder {
                      int16_t* decoded,
                      SpeechType* speech_type) override;
 
-  // Helper method. Writes |timestamp| and |samples| to |encoded| in a format
-  // that the FakeDecpdeFromFile decoder will understand. |encoded| must be at
-  // least 8 bytes long.
+  // Helper method. Writes |timestamp|, |samples| and
+  // |original_payload_size_bytes| to |encoded| in a format that the
+  // FakeDecodeFromFile decoder will understand. |encoded| must be at least 12
+  // bytes long.
   static void PrepareEncoded(uint32_t timestamp,
                              size_t samples,
+                             size_t original_payload_size_bytes,
                              rtc::ArrayView<uint8_t> encoded);
 
  private:
@@ -62,6 +64,8 @@ class FakeDecodeFromFile : public AudioDecoder {
   rtc::Optional<uint32_t> next_timestamp_from_input_;
   const int sample_rate_hz_;
   const bool stereo_;
+  size_t last_decoded_length_ = 0;
+  bool cng_mode_ = false;
 };
 
 }  // namespace test