Revert "Bug 2027433 Treat null input channels as zero in InterleaveAndConvertBuffer()"

This reverts commit e76fc5637a.

dom/media/AudioSegment.h

@@ -61,22 +61,15 @@ template <typename SrcT, typename DestT>
 static void
 InterleaveAndConvertBuffer(const SrcT* const* aSourceChannels,
                            uint32_t aLength, float aVolume,
-                           uint32_t aChannelCount,
+                           uint32_t aChannels,
                            DestT* aOutput)
 {
-  for (size_t channel = 0; channel < aChannelCount; ++channel) {
-    DestT* output = aOutput;
-    if (aSourceChannels[channel]) {
-      for (size_t i = 0; i < aLength; ++i) {
-        float v = AudioSampleToFloat(aSourceChannels[channel][i])*aVolume;
-        *output = FloatToAudioSample<DestT>(v);
-        output += aChannelCount;
-      }
-    } else {
-      for (size_t i = 0; i < aLength; ++i) {
-        *output = static_cast<DestT>(0);
-        output += aChannelCount;
-      }
+  DestT* output = aOutput;
+  for (size_t i = 0; i < aLength; ++i) {
+    for (size_t channel = 0; channel < aChannels; ++channel) {
+      float v = AudioSampleToFloat(aSourceChannels[channel][i])*aVolume;
+      *output = FloatToAudioSample<DestT>(v);
+      ++output;
     }
   }
 }