Bug 1633747 - Don't call NaN fixing code on platforms where samples are in i16.

Differential Revision: https://phabricator.services.mozilla.com/D73611

dom/media/GraphDriver.cpp

@@ -957,9 +957,11 @@ long AudioCallbackDriver::DataCallback(const AudioDataValue* aInputBuffer,
 
   mBuffer.BufferFilled();
 
+#ifdef MOZ_SAMPLE_TYPE_FLOAT32
   // Prevent returning NaN to the OS mixer, and propagating NaN into the reverse
   // stream of the AEC.
   NaNToZeroInPlace(aOutputBuffer, aFrames * mOutputChannelCount);
+#endif
 
   // Callback any observers for the AEC speaker data.  Note that one
   // (maybe) of these will be full-duplex, the others will get their input