Added FileReaderSync to dom.experimental

src/main/scala/org/scalajs/dom/experimental/FileReaderSync.scala

@@ -0,0 +1,48 @@
+package org.scalajs.dom.experimental
+
+import org.scalajs.dom.raw.Blob
+
+import scala.scalajs.js
+import scala.scalajs.js.annotation._
+import scala.scalajs.js.typedarray.ArrayBuffer
+
+/**
+ * The FileReaderSync interface allows to read File or Blob objects synchronously.
+ *
+ * This interface is only available in workers as it enables synchronous I/O that could potentially block.
+ *
+ * MDN
+ */
+@js.native
+@JSGlobal
+class FileReaderSync() extends js.Object {
+
+  /**
+   * The readAsArrayBuffer method is used to starts reading the contents of the
+   * specified Blob or File. When the read operation is finished, the readyState
+   * becomes DONE, and the loadend is triggered. At that time, the result attribute
+   * contains an ArrayBuffer representing the file's data.
+   *
+   * MDN
+   */
+  def readAsArrayBuffer(blob: Blob): ArrayBuffer = js.native
+
+  /**
+   * The readAsDataURL method is used to starts reading the contents of the specified
+   * Blob or File. When the read operation is finished, the readyState becomes DONE, and
+   * the loadend is triggered. At that time, the result attribute contains a data: URL
+   * representing the file's data as base64 encoded string.
+   *
+   * MDN
+   */
+  def readAsDataURL(blob: Blob): URL = js.native
+
+  /**
+   * The readAsText method is used to read the contents of the specified Blob or File.
+   * When the read operation is complete, the readyState is changed to DONE, the loadend
+   * is triggered, and the result attribute contains the contents of the file as a text string.
+   *
+   * MDN
+   */
+  def readAsText(blob: Blob, encoding: String = "UTF-8"): String = js.native
+}