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

webrtc/modules/audio_processing/audio_processing_unittest.cc

Index: webrtc/modules/audio_processing/audio_processing_unittest.cc
diff --git a/webrtc/modules/audio_processing/audio_processing_unittest.cc b/webrtc/modules/audio_processing/audio_processing_unittest.cc
index c56a57b4c3bdf2d96e7425518c67bbee418d59c8..4d97904c6869c25febb77933fc73fbf1760ddf7d 100644
--- a/webrtc/modules/audio_processing/audio_processing_unittest.cc
+++ b/webrtc/modules/audio_processing/audio_processing_unittest.cc
@@ -862,8 +862,6 @@ TEST_F(ApmTest, ChannelsInt16Interface) {
   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());
   }
 }