Update WebVR API based on prerelease 1.1 except window and navigator interface

third_party/WebKit/Source/modules/vr/VRDisplayEvent.idl

Index: third_party/WebKit/Source/modules/vr/VRDisplayEvent.idl
diff --git a/third_party/WebKit/Source/modules/vr/VRDisplayEvent.idl b/third_party/WebKit/Source/modules/vr/VRDisplayEvent.idl
index 31dcb48823d9afa4e6b02caa3378e27ade30fd5d..67babaaf49215e3e5b5a13725a897c806c1fb6ad 100644
--- a/third_party/WebKit/Source/modules/vr/VRDisplayEvent.idl
+++ b/third_party/WebKit/Source/modules/vr/VRDisplayEvent.idl
@@ -3,18 +3,16 @@
 // found in the LICENSE file.
 
 enum VRDisplayEventReason {
-    "connected",
-    "disconnected",
-    "navigation",
     "mounted",
+    "navigation",
     "unmounted"
 };
 
 // https://w3c.github.io/webvr/#interface-vrdisplayevent
 [
     OriginTrialEnabled=WebVR,
-    Constructor(DOMString type, optional VRDisplayEventInit eventInitDict),
+    Constructor(DOMString type, VRDisplayEventInit eventInitDict),
 ] interface VRDisplayEvent : Event {
     readonly attribute VRDisplay display;
-    readonly attribute VRDisplayEventReason reason;
+    readonly attribute VRDisplayEventReason? reason;
 };