Avoid render resampling when there is no need for render signal analysis.

webrtc/modules/audio_processing/audio_processing_unittest.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 844 matching lines @@
 
 TEST_F(ApmTest, ChannelsInt16Interface) {
   // Testing number of invalid and valid channels.
   Init(16000, 16000, 16000, 4, 4, 4, false);
 
   TestChangingChannelsInt16Interface(0, apm_->kBadNumberChannelsError);
 
   for (size_t i = 1; i < 4; i++) {
     TestChangingChannelsInt16Interface(i, kNoErr);
     EXPECT_EQ(i, apm_->num_input_channels());
-    // We always force the number of reverse channels used for processing to 1.

[peah-webrtc, 2017/05/19 08:07:47]

The changes in this CL breaks this test.

As this requirement does not make sense so I removed the test. The reason for
that it breaks is that if there is no processing, this CL changes the behavior
so that the reverse channels are not deinterleaved.

-    EXPECT_EQ(1u, apm_->num_reverse_channels());
   }
 }
 
 TEST_F(ApmTest, Channels) {
   // Testing number of invalid and valid channels.
   Init(16000, 16000, 16000, 4, 4, 4, false);
 
   TestChangingForwardChannels(0, 1, apm_->kBadNumberChannelsError);
   TestChangingReverseChannels(0, apm_->kBadNumberChannelsError);
 
@@ skipping 2001 matching lines @@
   // TODO(peah): Remove the testing for
   // apm->capture_nonlocked_.level_controller_enabled once the value in config_
   // is instead used to activate the level controller.
   EXPECT_FALSE(apm->capture_nonlocked_.level_controller_enabled);
   EXPECT_NEAR(kTargetLcPeakLeveldBFS,
               apm->config_.level_controller.initial_peak_level_dbfs,
               std::numeric_limits<float>::epsilon());
 }
 
 }  // namespace webrtc