Clean up the Config to enable 48kHz support in AudioProcessing

Now 48kHz is enabled by default.

BUG=webrtc:3146

Review URL: https://codereview.webrtc.org/1233393003

Cr-Commit-Position: refs/heads/master@{#9643}
diff --git a/webrtc/modules/audio_processing/audio_processing_impl.cc b/webrtc/modules/audio_processing/audio_processing_impl.cc
index 3d62439..bbfb771 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.cc
+++ b/webrtc/modules/audio_processing/audio_processing_impl.cc
@@ -210,8 +210,7 @@
 #endif
       beamformer_enabled_(config.Get<Beamforming>().enabled),
       beamformer_(beamformer),
-      array_geometry_(config.Get<Beamforming>().array_geometry),
-      supports_48kHz_(config.Get<AudioProcessing48kHzSupport>().enabled) {
+      array_geometry_(config.Get<Beamforming>().array_geometry) {
   echo_cancellation_ = new EchoCancellationImpl(this, crit_);
   component_list_.push_back(echo_cancellation_);
 
@@ -375,7 +374,7 @@
       std::min(api_format_.input_stream().sample_rate_hz(),
                api_format_.output_stream().sample_rate_hz());
   int fwd_proc_rate;
-  if (supports_48kHz_ && min_proc_rate > kSampleRate32kHz) {
+  if (min_proc_rate > kSampleRate32kHz) {
     fwd_proc_rate = kSampleRate48kHz;
   } else if (min_proc_rate > kSampleRate16kHz) {
     fwd_proc_rate = kSampleRate32kHz;
diff --git a/webrtc/modules/audio_processing/audio_processing_impl.h b/webrtc/modules/audio_processing/audio_processing_impl.h
index 0597cd9..a44b5a8 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.h
+++ b/webrtc/modules/audio_processing/audio_processing_impl.h
@@ -191,8 +191,6 @@
   const bool beamformer_enabled_;
   rtc::scoped_ptr<Beamformer<float>> beamformer_;
   const std::vector<Point> array_geometry_;
-
-  const bool supports_48kHz_;
 };
 
 }  // namespace webrtc
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index 6a8ef1b..0854844 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -116,15 +116,6 @@
   const std::vector<Point> array_geometry;
 };
 
-// Use to enable 48kHz support in audio processing. Must be provided through the
-// constructor. It will have no impact if used with
-// AudioProcessing::SetExtraOptions().
-struct AudioProcessing48kHzSupport {
-  AudioProcessing48kHzSupport() : enabled(true) {}
-  explicit AudioProcessing48kHzSupport(bool enabled) : enabled(enabled) {}
-  bool enabled;
-};
-
 static const int kAudioProcMaxNativeSampleRateHz = 32000;
 
 // The Audio Processing Module (APM) provides a collection of voice processing