Make sure that multiband processing is active when the residual echo detector is active.

BUG=webrtc:6525

Review-Url: https://codereview.webrtc.org/2481363008
Cr-Commit-Position: refs/heads/master@{#15081}
diff --git a/webrtc/modules/audio_processing/audio_processing_impl.cc b/webrtc/modules/audio_processing/audio_processing_impl.cc
index 90b1f2d..8078779 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.cc
+++ b/webrtc/modules/audio_processing/audio_processing_impl.cc
@@ -189,9 +189,11 @@
     const {
 #if WEBRTC_INTELLIGIBILITY_ENHANCER
   return CaptureMultiBandProcessingActive() ||
-         intelligibility_enhancer_enabled_ || voice_activity_detector_enabled_;
+         intelligibility_enhancer_enabled_ ||
+         voice_activity_detector_enabled_ || residual_echo_detector_enabled_;
 #else
-  return CaptureMultiBandProcessingActive() || voice_activity_detector_enabled_;
+  return CaptureMultiBandProcessingActive() ||
+         voice_activity_detector_enabled_ || residual_echo_detector_enabled_;
 #endif
 }
 
@@ -205,7 +207,8 @@
 bool AudioProcessingImpl::ApmSubmoduleStates::RenderMultiBandSubModulesActive()
     const {
   return RenderMultiBandProcessingActive() || echo_canceller_enabled_ ||
-         mobile_echo_controller_enabled_ || adaptive_gain_controller_enabled_;
+         mobile_echo_controller_enabled_ || adaptive_gain_controller_enabled_ ||
+         residual_echo_detector_enabled_;
 }
 
 bool AudioProcessingImpl::ApmSubmoduleStates::RenderMultiBandProcessingActive()