Reland of Fixed error for missing explict class initialization error on iOS WebRTC buildbots

webrtc/modules/audio_processing/aec3/render_buffer.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.
  */
 
 #include "webrtc/modules/audio_processing/aec3/render_buffer.h"
 
 #include <algorithm>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/modules/audio_processing/aec3/aec3_common.h"
 
 namespace webrtc {
 
 RenderBuffer::RenderBuffer(Aec3Optimization optimization,
                            size_t num_bands,
                            size_t num_partitions,
                            const std::vector<size_t> num_ffts_for_spectral_sums)
     : optimization_(optimization),
       fft_buffer_(num_partitions),
       spectrum_buffer_(num_partitions, std::array<float, kFftLengthBy2Plus1>()),
       spectral_sums_(num_ffts_for_spectral_sums.size(),
                      std::array<float, kFftLengthBy2Plus1>()),
-      last_block_(num_bands, std::vector<float>(kBlockSize, 0.f)) {
+      last_block_(num_bands, std::vector<float>(kBlockSize, 0.f)),
+      fft_() {
   // Current implementation only allows a maximum of one spectral sum lengths.
   RTC_DCHECK_EQ(1, num_ffts_for_spectral_sums.size());
   spectral_sums_length_ = num_ffts_for_spectral_sums[0];
   RTC_DCHECK_GE(fft_buffer_.size(), spectral_sums_length_);
 
   Clear();
 }
 
 RenderBuffer::~RenderBuffer() = default;
 
@@ skipping 45 matching lines @@
 
     for (size_t k = 0; k < spectral_sums_[0].size(); ++k) {
       spectral_sums_[0][k] += spectrum[k];
     }
 
     position = position < (fft_buffer_.size() - 1) ? position + 1 : 0;
   }
 }
 
 }  // namespace webrtc