Implement Encoding API

Source/modules/encoding/TextEncoder.idl

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-// http://www.w3.org/TR/ime-api/
 [
-    NoInterfaceObject
-] interface Composition {
-    readonly attribute DOMString text;
-    readonly attribute long selectionStart;
-    readonly attribute long selectionEnd;
-    sequence<unsigned long> getSegments();
+    EnabledAtRuntime=EncodingAPI,
+    GlobalContext=Window&WorkerGlobalScope,
+    Constructor([Default=NullString] optional DOMString utfLabel),
+    ConstructorRaisesException
+] interface TextEncoder {
+    readonly attribute DOMString encoding;
+    Uint8Array encode([Default=NullString] optional DOMString input, optional Dictionary options);
 };