Switch back to using traits for now.

Author: yilinwei

dom/src/main/scala/org/scalajs/dom/GainNode.scala

@@ -6,7 +6,6 @@
 package org.scalajs.dom
 
 import scala.scalajs.js
-import scala.scalajs.js.annotation._
 
 /** The GainNode interface represents a change in volume. It is an AudioNode audio-processing module that causes a given
   * gain to be applied to the input data before its propagation to the output. A GainNode always has exactly one input
@@ -24,10 +23,15 @@ import scala.scalajs.js.annotation._
   *   - Channel count: 2 (not used in the default count mode)
   *   - Channel interpretation: "speakers"
   */
-@JSGlobal
 @js.native
-class GainNode(context: BaseAudioContext, options: GainNodeOptions = js.native) extends AudioNode {
+trait GainNode extends AudioNode {
 
   /** Is an a-rate AudioParam representing the amount of gain to apply. */
   val gain: AudioParam = js.native
 }
+
+object GainNode {
+
+  def apply(context: BaseAudioContext, options: js.UndefOr[GainNodeOptions] = js.undefined): GainNode =
+    js.Dynamic.newInstance(js.Dynamic.global.GainNode)(context, options).asInstanceOf[GainNode]
+}

dom/src/main/scala/org/scalajs/dom/OscillatorNode.scala

@@ -6,7 +6,6 @@
 package org.scalajs.dom
 
 import scala.scalajs.js
-import scala.scalajs.js.annotation._
 
 /** The OscillatorNode interface represents a periodic waveform, like a sine wave. It is an AudioNode audio-processing
   * module that causes a given frequency of sine wave to be created — in effect, a constant tone.
@@ -20,9 +19,8 @@ import scala.scalajs.js.annotation._
   *   - Channel count: 2 (not used in the default count mode)
   *   - Channel interpretation: speakers
   */
-@JSGlobal
 @js.native
-class OscillatorNode(context: BaseAudioContext, options: OscillatorNodeOptions = js.native)
+trait OscillatorNode
     extends AudioScheduledSourceNode {
 
   /** An a-rate AudioParam representing the frequency of oscillation in hertz (though the AudioParam returned is
@@ -45,3 +43,8 @@ class OscillatorNode(context: BaseAudioContext, options: OscillatorNodeOptions =
     */
   def setPeriodicWave(wave: PeriodicWave): Unit = js.native
 }
+
+object OscillatorNode {
+  def apply(context: BaseAudioContext, options: js.UndefOr[OscillatorNodeOptions] = js.undefined): GainNode =
+    js.Dynamic.newInstance(js.Dynamic.global.GainNode)(context, options).asInstanceOf[GainNode]
+}