Adding more refined control over choice of band-splitting

This CL allows the user to have more refined control over what band
splitting-scheme is used inside the audio processing module.


Bug: webrtc:6181
Change-Id: I236c3b1f96ab80cc4ffb8c39c045c034764567a1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/152480
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29189}

modules/audio_processing/include/audio_processing.cc

@@ -11,6 +11,7 @@
 #include "modules/audio_processing/include/audio_processing.h"
 
 #include "rtc_base/strings/string_builder.h"
+#include "rtc_base/system/arch.h"
 
 namespace webrtc {
 namespace {
@@ -51,11 +52,22 @@ std::string GainController2LevelEstimatorToString(
   }
 }
 
+int GetDefaultMaxInternalRate() {
+#ifdef WEBRTC_ARCH_ARM_FAMILY
+  return 32000;
+#else
+  return 48000;
+#endif
+}
+
 }  // namespace
 
 void CustomProcessing::SetRuntimeSetting(
     AudioProcessing::RuntimeSetting setting) {}
 
+AudioProcessing::Config::Pipeline::Pipeline()
+    : maximum_internal_processing_rate(GetDefaultMaxInternalRate()) {}
+
 std::string AudioProcessing::Config::ToString() const {
   char buf[1024];
   rtc::SimpleStringBuilder builder(buf);