Revert of Remove the deprecated EncodeInternal interface from AudioEncoder

webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red_unittest.cc

Index: webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red_unittest.cc
diff --git a/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red_unittest.cc b/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red_unittest.cc
index 22b2ceb5f79f6aaa829ba5b7c0d2cdb1fb5cca1a..c73cb9f2096528b740049141183d605da143dd8e 100644
--- a/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red_unittest.cc
+++ b/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red_unittest.cc
@@ -26,6 +26,7 @@
 namespace webrtc {
 
 namespace {
+static const size_t kMockMaxEncodedBytes = 1000;
 static const size_t kMaxNumSamples = 48 * 10 * 2;  // 10 ms @ 48 kHz stereo.
 }
 
@@ -45,6 +46,8 @@
     EXPECT_CALL(*mock_encoder_, NumChannels()).WillRepeatedly(Return(1U));
     EXPECT_CALL(*mock_encoder_, SampleRateHz())
         .WillRepeatedly(Return(sample_rate_hz_));
+    EXPECT_CALL(*mock_encoder_, MaxEncodedBytes())
+        .WillRepeatedly(Return(kMockMaxEncodedBytes));
   }
 
   void TearDown() override {