AudioCodingModuleImpl: Stop failing artificially for non-Opus encoders

webrtc/modules/audio_coding/test/TestVADDTX.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 216 matching lines @@
     EXPECT_TRUE(vad_enabled_); // WebRTC DTX cannot run without WebRTC VAD.
   } else {
     // Using no DTX should not affect setting of VAD.
     EXPECT_EQ(enable_vad, vad_enabled_);
   }
 }
 
 // Following is the implementation of TestOpusDtx.
 void TestOpusDtx::Perform() {
 #ifdef WEBRTC_CODEC_ISAC
-  // If we set other codec than Opus, DTX cannot be toggled.
+  // If we set other codec than Opus, DTX cannot be switched on.
   RegisterCodec(kIsacWb);
   EXPECT_EQ(-1, acm_send_->EnableOpusDtx());
-  EXPECT_EQ(-1, acm_send_->DisableOpusDtx());
+  EXPECT_EQ(0, acm_send_->DisableOpusDtx());
 #endif
 
 #ifdef WEBRTC_CODEC_OPUS
   int expects[] = {0, 1, 0, 0, 0};
 
   // Register Opus as send codec
   std::string out_filename = webrtc::test::OutputPath() +
       "testOpusDtx_outFile_mono.pcm";
   RegisterCodec(kOpus);
   EXPECT_EQ(0, acm_send_->DisableOpusDtx());
@@ skipping 16 matching lines @@
 
   EXPECT_EQ(0, acm_send_->EnableOpusDtx());
 
   expects[kEmptyFrame] = 1;
   Run(webrtc::test::ResourcePath("audio_coding/teststereo32kHz", "pcm"),
       32000, 2, out_filename, true, expects);
 #endif
 }
 
 }  // namespace webrtc