--- a/dom/media/AudioConfig.h
+++ b/dom/media/AudioConfig.h
@@ -8,19 +8,16 @@
 
 #include <cstdint>
 #include <initializer_list>
 #include "mozilla/MathAlgorithms.h"
 #include "nsTArray.h"
 
 namespace mozilla {
 
-  // Maximum channel number we can currently handle (7.1)
-#define MAX_AUDIO_CHANNELS 8
-
 class AudioConfig
 {
 public:
   // Channel definition is conveniently defined to be in the same order as
   // WAVEFORMAT && SMPTE, even though this is unused for now.
   enum Channel
   {
     CHANNEL_INVALID = -1,
@@ -233,16 +230,21 @@ public:
 #error "Not supported audio type"
 #endif
   };
 
   AudioConfig(const ChannelLayout& aChannelLayout,
               uint32_t aRate,
               AudioConfig::SampleFormat aFormat = FORMAT_DEFAULT,
               bool aInterleaved = true);
+  AudioConfig(const ChannelLayout& aChannelLayout,
+              uint32_t aChannels,
+              uint32_t aRate,
+              AudioConfig::SampleFormat aFormat = FORMAT_DEFAULT,
+              bool aInterleaved = true);
   // Will create a channel configuration from default SMPTE ordering.
   AudioConfig(uint32_t aChannels,
               uint32_t aRate,
               AudioConfig::SampleFormat aFormat = FORMAT_DEFAULT,
               bool aInterleaved = true);
 
   const ChannelLayout& Layout() const { return mChannelLayout; }
   uint32_t Channels() const