Implement VTTCue.region and sync the VTTRegion interface

third_party/WebKit/Source/core/html/track/vtt/VTTRegion.idl

Index: third_party/WebKit/Source/core/html/track/vtt/VTTRegion.idl
diff --git a/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.idl b/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.idl
index 172523b4cc957b62bd1054e670c30aa7c5146b14..6744153f0b3d40c58dea4dce3a27ba012d269c10 100644
--- a/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.idl
+++ b/third_party/WebKit/Source/core/html/track/vtt/VTTRegion.idl
@@ -25,22 +25,17 @@
 
 // https://w3c.github.io/webvtt/#the-vttregion-interface
 
+enum ScrollSetting { "" /* none */, "up" };
+
 [
     Constructor,
     RuntimeEnabled=WebVTTRegions,
 ] interface VTTRegion {
     [RaisesException=Setter] attribute double width;
-    // TODO(foolip): height should be called lines.
-    [RaisesException=Setter] attribute long height;
+    [RaisesException=Setter] attribute long lines;
     [RaisesException=Setter] attribute double regionAnchorX;
     [RaisesException=Setter] attribute double regionAnchorY;
     [RaisesException=Setter] attribute double viewportAnchorX;
     [RaisesException=Setter] attribute double viewportAnchorY;
-    // TODO(philip): scroll should be of type ScrollSetting.
-    [RaisesException=Setter] attribute DOMString scroll;
-
-    // TODO(foolip): The track/id attributes are gone from the spec:
-    // https://www.w3.org/Bugs/Public/show_bug.cgi?id=24380
-    readonly attribute TextTrack track;
-    attribute DOMString id;
+    attribute ScrollSetting scroll;
 };