Workaround a (Windows) linker bug when doing a PGO build.

webrtc/modules/audio_coding/main/acm2/audio_coding_module_impl.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 254 matching lines @@
 
   return codec_manager_.CurrentEncoder()->SampleRateHz();
 }
 
 // Get encode bitrate.
 // Adaptive rate codecs return their current encode target rate, while other
 // codecs return there longterm avarage or their fixed rate.
 // TODO(henrik.lundin): Remove; not used.
 int AudioCodingModuleImpl::SendBitrate() const {
   FATAL() << "Deprecated";
+  // This return statement is required to workaround a bug in VS2013 Update 4
+  // when turning on the whole program optimizations. Without hit the linker
+  // will hang because it doesn't seem to find an exit path for this function.
+  // This is likely a bug in link.exe and would probably be fixed in VS2015.
+  return -1;
   //  CriticalSectionScoped lock(acm_crit_sect_);
   //
   //  if (!codec_manager_.current_encoder()) {
   //    WEBRTC_TRACE(webrtc::kTraceStream, webrtc::kTraceAudioCoding, id_,
   //                 "SendBitrate Failed, no codec is registered");
   //    return -1;
   //  }
   //
   //  WebRtcACMCodecParams encoder_param;
   //  codec_manager_.current_encoder()->EncoderParams(&encoder_param);
@@ skipping 973 matching lines @@
       *channels = 1;
       break;
 #endif
     default:
       FATAL() << "Codec type " << codec_type << " not supported.";
   }
   return true;
 }
 
 }  // namespace webrtc