Remove Sync GetPose VRService call, implement VRVSyncProvider

device/vr/vr_service.mojom

Index: device/vr/vr_service.mojom
diff --git a/device/vr/vr_service.mojom b/device/vr/vr_service.mojom
index d41b1a9ed09da0fe5157c51d9de5af058d4e1a0d..b7d8515825e0a45e1f521f051a7e276f5d0c41dc 100644
--- a/device/vr/vr_service.mojom
+++ b/device/vr/vr_service.mojom
@@ -3,6 +3,8 @@
 
 module device.mojom;
 
+import "mojo/common/time.mojom";
+
 // A field of view, given by 4 degrees describing the view from a center point.
 struct VRFieldOfView {
   float upDegrees;
@@ -84,14 +86,17 @@ interface VRServiceClient {
 };
 
 interface VRDisplay {
-  [Sync]
-  GetPose() => (VRPose? pose);
   ResetPose();
 
   RequestPresent(bool secureOrigin) => (bool success);
   ExitPresent();
   SubmitFrame(VRPose? pose);
   UpdateLayerBounds(VRLayerBounds leftBounds, VRLayerBounds rightBounds);
+  GetVRVSyncProvider(VRVSyncProvider& request);
+};
+
+interface VRVSyncProvider {
+  GetVSync() => (VRPose? pose, mojo.common.mojom.TimeDelta time);
 };
 
 interface VRDisplayClient {