Looping one-sample AudioBufferSourceNode should work.

Source/modules/webaudio/AudioBufferSourceNode.cpp

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 218 matching lines @@
         double loopEndFrame = m_loopEnd * buffer()->sampleRate();
 
         virtualEndFrame = std::min(loopEndFrame, virtualEndFrame);
         virtualDeltaFrames = virtualEndFrame - loopStartFrame;
     }
 
 
     double pitchRate = totalPitchRate();
 
     // Sanity check that our playback rate isn't larger than the loop size.
-    if (pitchRate >= virtualDeltaFrames)
+    if (pitchRate > virtualDeltaFrames)
         return false;
 
     // Get local copy.
     double virtualReadIndex = m_virtualReadIndex;
 
     // Render loop - reading from the source buffer to the destination using linear interpolation.
     int framesToProcess = numberOfFrames;
 
     const float** sourceChannels = m_sourceChannels.get();
     float** destinationChannels = m_destinationChannels.get();
@@ skipping 253 matching lines @@
 {
     visitor->trace(m_buffer);
     visitor->trace(m_playbackRate);
     visitor->trace(m_pannerNode);
     AudioScheduledSourceNode::trace(visitor);
 }
 
 } // namespace blink
 
 #endif // ENABLE(WEB_AUDIO)