Reland of mojo VR interface simpified.

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 25 matching lines @@
   uint32 renderWidth;
   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 VRDisplayInfo {
+  uint32 index;
+  string displayName;
+  VRDisplayCapabilities capabilities;
+  VRStageParameters? stageParameters;
+  VREyeParameters leftEye;
+  VREyeParameters rightEye;
 };
 
 struct VRLayerBounds {
-   float left;
-   float top;
-   float width;
-   float height;
+  float left;
+  float top;
+  float width;
+  float height;
 };
 
+// TODO(shaobo.yan@intel.com) : Add comments to describe these interfaces about how to use and where they live.
 interface VRService {
-  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);
+  // TODO(shaobo.yan@intel.com) : Use a factory function which took a VRServiceClient
+  // so we would never have a half-initialized VRService.
+  SetClient(VRServiceClient client) => (uint32 numberOfConnectedDevices);
 };
 
 interface VRServiceClient {
-  OnDisplayChanged(VRDisplay display);
-  OnExitPresent(uint32 index);
-  OnDisplayConnected(VRDisplay display);
-  OnDisplayDisconnected(uint32 index);
+  OnDisplayConnected(VRDisplay display, VRDisplayClient& request, VRDisplayInfo displayInfo);
 };
+
+interface VRDisplay {
+
+  [Sync]
+  GetPose() => (VRPose? pose);
+  ResetPose();
+
+  RequestPresent(bool secureOrigin) => (bool success);
+  ExitPresent();
+  SubmitFrame(VRPose? pose);
+  UpdateLayerBounds(VRLayerBounds leftBounds, VRLayerBounds rightBounds);
+};
+
+interface VRDisplayClient {
+  OnDisplayChanged(VRDisplayInfo display);
+  OnExitPresent();
+};