Give Audio{De,En}coderIsac* an "Impl" suffix, to free up the original names

webrtc/modules/audio_coding/codecs/builtin_audio_encoder_factory_internal.cc

 /*
  *  Copyright (c) 2017 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 50 matching lines @@
 };
 
 NamedEncoderFactory encoder_factories[] = {
 #ifdef WEBRTC_CODEC_G722
     NamedEncoderFactory::ForEncoder<AudioEncoderG722Impl>(),
 #endif
 #ifdef WEBRTC_CODEC_ILBC
     NamedEncoderFactory::ForEncoder<AudioEncoderIlbcImpl>(),
 #endif
 #if defined(WEBRTC_CODEC_ISACFX)
-    NamedEncoderFactory::ForEncoder<AudioEncoderIsacFix>(),
+    NamedEncoderFactory::ForEncoder<AudioEncoderIsacFixImpl>(),
 #elif defined(WEBRTC_CODEC_ISAC)
-    NamedEncoderFactory::ForEncoder<AudioEncoderIsac>(),
+    NamedEncoderFactory::ForEncoder<AudioEncoderIsacFloatImpl>(),
 #endif
 
 #ifdef WEBRTC_CODEC_OPUS
     NamedEncoderFactory::ForEncoder<AudioEncoderOpus>(),
 #endif
     NamedEncoderFactory::ForEncoder<AudioEncoderPcm16B>(),
     NamedEncoderFactory::ForEncoder<AudioEncoderPcmA>(),
     NamedEncoderFactory::ForEncoder<AudioEncoderPcmU>(),
 };
 }  // namespace
@@ skipping 51 matching lines @@
   }
 };
 
 rtc::scoped_refptr<AudioEncoderFactory>
 CreateBuiltinAudioEncoderFactoryInternal() {
   return rtc::scoped_refptr<AudioEncoderFactory>(
       new rtc::RefCountedObject<BuiltinAudioEncoderFactory>());
 }
 
 }  // namespace webrtc