mojo VR interface simplified

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.
+// Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file.
 
-module device;
+module device.mojom;
 
 // A field of view, given by 4 degrees describing the view from a center point.
 struct VRFieldOfView {
   float upDegrees;
   float downDegrees;
   float leftDegrees;
   float rightDegrees;
 };
 
 // A display's position, orientation, velocity, and acceleration state at the
@@ skipping 26 matching lines @@
   uint32 renderHeight;
 };
 
 struct VRStageParameters {
   array<float, 16> standingTransform;
   float sizeX;
   float sizeZ;
 };
 
 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 {
+  GetDisplays() => (bool success);
   SetClient(VRServiceClient client);
-
-  GetDisplays() => (array<VRDisplay> displays);
-  [Sync]
-  GetPose(uint32 index) => (VRPose? pose);
-  ResetPose(uint32 index);
-
-  RequestPresent(uint32 index, bool secureOrigin) => (bool success);
-  ExitPresent(uint32 index);
-  SubmitFrame(uint32 index, VRPose? pose);
-  UpdateLayerBounds(uint32 index, VRLayerBounds leftBounds, VRLayerBounds rightBounds);
 };
 
 interface VRServiceClient {
+  [Sync]
+  GetDisplayClient() => (VRDisplayClient? client);
+};
+
+interface VRDevice {
+  [Sync]
+  GetPose() => (VRPose? pose);
+  ResetPose();
+
+  RequestPresent(bool secureOrigin) => (bool success);
+  ExitPresent();
+  SubmitFrame(VRPose? pose);
+  UpdateLayerBounds(VRLayerBounds leftBounds, VRLayerBounds rightBounds);
+};
+
+interface VRDisplayClient {
+  RegisterDevice(VRDevice? device_client);
+  UpdateDisplayInfo(VRDisplay display);
+
   OnDisplayChanged(VRDisplay display);
-  OnExitPresent(uint32 index);
+  OnExitPresent();
   OnDisplayConnected(VRDisplay display);
-  OnDisplayDisconnected(uint32 index);
+  OnDisplayDisconnected();
 };