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

Source/modules/screen_orientation/ScreenOrientation.idl

Index: Source/modules/screen_orientation/ScreenOrientation.idl
diff --git a/Source/modules/screen_orientation/ScreenOrientation.idl b/Source/modules/screen_orientation/ScreenOrientation.idl
index 057ad37c57456f156759e2b2ef6064941351d3be..f869dc547f380072cd5ab3d132e823b58d0367ab 100644
--- a/Source/modules/screen_orientation/ScreenOrientation.idl
+++ b/Source/modules/screen_orientation/ScreenOrientation.idl
@@ -1,6 +1,13 @@
 // 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",
@@ -13,22 +20,12 @@
     "landscape-secondary"
 };
 
-enum OrientationType {
-    "portrait-primary",
-    "portrait-secondary",
-    "landscape-primary",
-    "landscape-secondary"
+[
+    RuntimeEnabled=ScreenOrientation
+] partial interface Screen {
+    readonly attribute OrientationType orientation;
+
+    [CallWith=ScriptState] Promise lockOrientation(OrientationLockType orientation);
+
+    void unlockOrientation();
 };
-
-[
-    GarbageCollected,
-    RuntimeEnabled=ScreenOrientation
-] interface ScreenOrientation : EventTarget {
-    readonly attribute unsigned short angle;
-    readonly attribute DOMString type;
-
-    [CallWith=ScriptState] Promise lock(OrientationLockType orientation);
-    void unlock();
-
-    attribute EventHandler onchange;
-};