Moved the AEC C code to be built using C++

webrtc/modules/audio_processing/echo_cancellation_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.
  */
 
 #include "webrtc/modules/audio_processing/echo_cancellation_impl.h"
 
 #include <assert.h>
 #include <string.h>
 
-extern "C" {
 #include "webrtc/modules/audio_processing/aec/aec_core.h"
-}
 #include "webrtc/modules/audio_processing/aec/echo_cancellation.h"
 #include "webrtc/modules/audio_processing/audio_buffer.h"
 
 namespace webrtc {
 
 typedef void Handle;
 
 namespace {
 int16_t MapSetting(EchoCancellation::SuppressionLevel level) {
   switch (level) {
@@ skipping 474 matching lines @@
   // Not locked as it only relies on APM public API which is threadsafe.
   return apm_->num_output_channels() * apm_->num_reverse_channels();
 }
 
 int EchoCancellationImpl::GetHandleError(void* handle) const {
   // Not locked as it does not rely on anything in the state.
   assert(handle != NULL);
   return AudioProcessing::kUnspecifiedError;
 }
 }  // namespace webrtc