Adds volume level measurements to the AudioInputController for low-latency clients

media/audio/audio_power_monitor.h

Index: media/audio/audio_power_monitor.h
diff --git a/media/audio/audio_power_monitor.h b/media/audio/audio_power_monitor.h
index f840bbf6b9f0f23912b7af870ba080a552f34202..d3e86d46d323cef6eda981b03b89f01370483834 100644
--- a/media/audio/audio_power_monitor.h
+++ b/media/audio/audio_power_monitor.h
@@ -10,6 +10,7 @@
 
 #include "base/callback.h"
 #include "base/synchronization/lock.h"
+#include "media/audio/audio_parameters.h"
 #include "media/base/media_export.h"
 
 // An audio signal power monitor.  It is periodically provided an AudioBus by
@@ -40,6 +41,7 @@ class MEDIA_EXPORT AudioPowerMonitor {
   // level; and is the amount of time it takes a zero power level to increase to
   // ~63.2% of maximum given a step input signal.
   AudioPowerMonitor(int sample_rate, const base::TimeDelta& time_constant);
+  AudioPowerMonitor(const AudioParameters& params);
 
   ~AudioPowerMonitor();
 
@@ -50,6 +52,7 @@ class MEDIA_EXPORT AudioPowerMonitor {
   // Scan more |frames| of audio data from |buffer|.  It is safe to call this
   // from a real-time priority thread.
   void Scan(const AudioBus& buffer, int frames);
+  void Scan(const void* data, uint32 size);
 
   // Returns the current power level in dBFS and clip status.  Clip status is
   // true whenever any *one* sample scanned exceeded maximum amplitude since
@@ -79,6 +82,9 @@ class MEDIA_EXPORT AudioPowerMonitor {
   float power_reading_;
   bool clipped_reading_;
 
+  scoped_ptr<AudioBus> audio_bus_;
+  AudioParameters params_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioPowerMonitor);
 };