Major AEC3 render pipeline changes

webrtc/modules/audio_processing/aec3/decimator_by_4.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/decimator_by_4.h"
 
 #include "webrtc/base/checks.h"
 
 namespace webrtc {
 namespace {
 
 // [B,A] = butter(2,1500/16000) which are the same as [B,A] =
 // butter(2,750/8000).
 const CascadedBiQuadFilter::BiQuadCoefficients kLowPassFilterCoefficients = {
     {0.0179f, 0.0357f, 0.0179f},
     {-1.5879f, 0.6594f}};
 
 }  // namespace
 
 DecimatorBy4::DecimatorBy4()
     : low_pass_filter_(kLowPassFilterCoefficients, 3) {}
 
 void DecimatorBy4::Decimate(rtc::ArrayView<const float> in,
-                            std::array<float, kSubBlockSize>* out) {
+                            rtc::ArrayView<float> out) {
   RTC_DCHECK_EQ(kBlockSize, in.size());
-  RTC_DCHECK(out);
+  RTC_DCHECK_EQ(kSubBlockSize, out.size());
   std::array<float, kBlockSize> x;
 
   // Limit the frequency content of the signal to avoid aliasing.
   low_pass_filter_.Process(in, x);
 
   // Downsample the signal.
-  for (size_t j = 0, k = 0; j < out->size(); ++j, k += 4) {
+  for (size_t j = 0, k = 0; j < out.size(); ++j, k += 4) {
     RTC_DCHECK_GT(kBlockSize, k);
-    (*out)[j] = x[k];
+    out[j] = x[k];
   }
 }
 
 }  // namespace webrtc