Plumbing through more WebVR presentation code

device/vr/vr_service.mojom

 // Copyright 2015 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.
 
 module device;
 
 // A field of view, given by 4 degrees describing the view from a center point.
 struct VRFieldOfView {
   float upDegrees;
   float downDegrees;
@@ skipping 36 matching lines @@
 
 struct VRDisplay {
    uint32 index;
    string displayName;
    VRDisplayCapabilities capabilities;
    VRStageParameters? stageParameters;
    VREyeParameters leftEye;
    VREyeParameters rightEye;
 };
 
+struct VRLayerBounds {
+   float left;
+   float top;
+   float width;
+   float height;
+};
+
 interface VRService {
   SetClient(VRServiceClient client);
 
   GetDisplays() => (array<VRDisplay> displays);
   [Sync]
   GetPose(uint32 index) => (VRPose pose);
   ResetPose(uint32 index);
+
+  RequestPresent(uint32 index);
+  ExitPresent(uint32 index);
+  SubmitFrame(uint32 index);
+  UpdateLayerBounds(uint32 index, VRLayerBounds leftBounds, VRLayerBounds rightBounds);
 };
 
 interface VRServiceClient {
   OnDisplayChanged(VRDisplay display);
 };