Fix ReadableStream binary compatibility and test compilation.

Author: ptrdom

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

@@ -1,19 +1,14 @@
 package org.scalajs.dom
 
 import scala.scalajs.js
-import scala.scalajs.js.annotation.JSGlobal
 
 /** defined at [[https://streams.spec.whatwg.org/#readable-stream ¶2.1. Readable Streams]] of whatwg Streams spec.
   *
   * @tparam T
   *   Type of the Chunks returned by the Stream. Can't make it coveriant, due to T
   */
 @js.native
-@JSGlobal
-class ReadableStream[+T](
-    underlyingSource: js.UndefOr[ReadableStreamUnderlyingSource[T]],
-    queuingStrategy: js.UndefOr[ReadableStreamQueuingStrategy[T]] = js.undefined
-) extends js.Object {
+trait ReadableStream[+T] extends js.Object {
 
   /** The locked getter returns whether or not the readable stream is locked to a reader.
     *
@@ -97,3 +92,18 @@ class ReadableStream[+T](
     */
   def tee(): js.Array[_ <: ReadableStream[T]] = js.native // TODO js.Tuple2[ReadableStream[T], ReadableStream[T]]
 }
+
+object ReadableStream {
+
+  def apply[T](
+      underlyingSource: js.UndefOr[ReadableStreamUnderlyingSource[T]],
+      queuingStrategy: js.UndefOr[ReadableStreamQueuingStrategy[T]] = js.undefined
+  ): ReadableStream[T] = {
+    js.Dynamic
+      .newInstance(js.Dynamic.global.selectDynamic("ReadableStream"))(
+          underlyingSource.asInstanceOf[js.Any],
+          queuingStrategy.asInstanceOf[js.Any]
+      )
+      .asInstanceOf[ReadableStream[T]]
+  }
+}

tests-shared/src/main/scala/org/scalajs/dom/tests/shared/SharedTests.scala

@@ -7,7 +7,6 @@ import org.scalajs.dom.tests.shared.AsyncTesting._
 import scala.concurrent.Future
 import scala.scalajs.js
 import scala.scalajs.js.Thenable.Implicits._
-import scala.scalajs.js.|
 
 trait SharedTests {
 
@@ -52,13 +51,13 @@ trait SharedTests {
         Tuna("red")
     )
 
-    val stream = new ReadableStream[Tuna](
+    val stream = ReadableStream[Tuna](
         new ReadableStreamUnderlyingSource[Tuna] {
-          start = { controller: ReadableStreamController[Tuna] =>
+          start = { (controller: ReadableStreamController[Tuna]) =>
             controller.enqueue(Tuna("blue"))
             controller.enqueue(Tuna("red"))
             controller.close()
-          }.asInstanceOf[js.UndefOr[js.Function1[ReadableStreamController[Tuna], Unit | js.Promise[Unit]]]]
+          }: js.Function1[ReadableStreamController[Tuna], Unit]
         }
     )