Revert of [screen-orientation] Update implementation to match recent spec changes.

Source/modules/screen_orientation/ScreenOrientation.idl

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+enum OrientationType {
+    "portrait-primary",
+    "portrait-secondary",
+    "landscape-primary",
+    "landscape-secondary"
+};
+
 enum OrientationLockType {
     "any",
     "natural",
     "landscape",
     "portrait",
     "portrait-primary",
     "portrait-secondary",
     "landscape-primary",
     "landscape-secondary"
 };
 
-enum OrientationType {
-    "portrait-primary",
-    "portrait-secondary",
-    "landscape-primary",
-    "landscape-secondary"
-};
-
 [
-    GarbageCollected,
     RuntimeEnabled=ScreenOrientation
-] interface ScreenOrientation : EventTarget {
-    readonly attribute unsigned short angle;
-    readonly attribute DOMString type;
+] partial interface Screen {
+    readonly attribute OrientationType orientation;
 
-    [CallWith=ScriptState] Promise lock(OrientationLockType orientation);
-    void unlock();
+    [CallWith=ScriptState] Promise lockOrientation(OrientationLockType orientation);
 
-    attribute EventHandler onchange;
+    void unlockOrientation();
 };