AudioDecoder: Remove the default implementation of SampleRateHz

webrtc/modules/audio_coding/neteq/mock/mock_external_decoder_pcm16b.h

Index: webrtc/modules/audio_coding/neteq/mock/mock_external_decoder_pcm16b.h
diff --git a/webrtc/modules/audio_coding/neteq/mock/mock_external_decoder_pcm16b.h b/webrtc/modules/audio_coding/neteq/mock/mock_external_decoder_pcm16b.h
index 42c17ae054c555b30fae5e9194000bb1e3055391..23a3ec4c99ea27a236607a78686fffc20c91fbbd 100644
--- a/webrtc/modules/audio_coding/neteq/mock/mock_external_decoder_pcm16b.h
+++ b/webrtc/modules/audio_coding/neteq/mock/mock_external_decoder_pcm16b.h
@@ -23,11 +23,11 @@ namespace webrtc {
 using ::testing::_;
 using ::testing::Invoke;
 
-// Implement an external version of the PCM16b decoder. This is a copy from
-// audio_decoder_impl.{cc, h}.
+// Implement an external version of the PCM16b decoder.
 class ExternalPcm16B : public AudioDecoder {
  public:
-  ExternalPcm16B() {}
+  explicit ExternalPcm16B(int sample_rate_hz)
+      : sample_rate_hz_(sample_rate_hz) {}
   void Reset() override {}
 
   int DecodeInternal(const uint8_t* encoded,
@@ -35,21 +35,24 @@ class ExternalPcm16B : public AudioDecoder {
                      int sample_rate_hz,
                      int16_t* decoded,
                      SpeechType* speech_type) override {
+    EXPECT_EQ(sample_rate_hz_, sample_rate_hz);
     size_t ret = WebRtcPcm16b_Decode(encoded, encoded_len, decoded);
     *speech_type = ConvertSpeechType(1);
     return static_cast<int>(ret);
   }
+  int SampleRateHz() const override { return sample_rate_hz_; }
   size_t Channels() const override { return 1; }
 
  private:
+  const int sample_rate_hz_;
   RTC_DISALLOW_COPY_AND_ASSIGN(ExternalPcm16B);
 };
 
 // Create a mock of ExternalPcm16B which delegates all calls to the real object.
 // The reason is that we can then track that the correct calls are being made.
-class MockExternalPcm16B : public ExternalPcm16B {
+class MockExternalPcm16B : public AudioDecoder {
  public:
-  MockExternalPcm16B() {
+  explicit MockExternalPcm16B(int sample_rate_hz) : real_(sample_rate_hz) {
     // By default, all calls are delegated to the real object.
     ON_CALL(*this, DecodeInternal(_, _, _, _, _))
         .WillByDefault(Invoke(&real_, &ExternalPcm16B::DecodeInternal));
@@ -85,6 +88,9 @@ class MockExternalPcm16B : public ExternalPcm16B {
   MOCK_METHOD0(ErrorCode,
       int());
 
+  int SampleRateHz() const /* override */ { return real_.SampleRateHz(); }
+  size_t Channels() const /* override */ { return real_.Channels(); }
+
  private:
   ExternalPcm16B real_;
 };