Remove type of panningModelType "soundfield".

Source/modules/webaudio/PannerNode.idl

 /*
  * 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 11 matching lines @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 [
     NoInterfaceObject,
     Conditional=WEB_AUDIO
 ] interface PannerNode : AudioNode {
     // Panning model
     const unsigned short EQUALPOWER = 0;
     const unsigned short HRTF = 1;
-    const unsigned short SOUNDFIELD = 2;
 
     // Distance model
     const unsigned short LINEAR_DISTANCE = 0;
     const unsigned short INVERSE_DISTANCE = 1;
     const unsigned short EXPONENTIAL_DISTANCE = 2;
 
     // Default model for stereo is HRTF
     [Custom=Setter] attribute DOMString panningModel;
 
     // Uses a 3D cartesian coordinate system
     void setPosition(float x, float y, float z);
     void setOrientation(float x, float y, float z);
     void setVelocity(float x, float y, float z);
 
     // Distance model
     [Custom=Setter] attribute DOMString distanceModel;
 
     attribute double refDistance;
     attribute double maxDistance;
     attribute double rolloffFactor;
 
     // Directional sound cone
     attribute double coneInnerAngle;
     attribute double coneOuterAngle;
     attribute double coneOuterGain;
 };