Add event listening function to openvr device

device/vr/openvr/openvr_device.cc

Index: device/vr/openvr/openvr_device.cc
diff --git a/device/vr/openvr/openvr_device.cc b/device/vr/openvr/openvr_device.cc
index f129d977e0a77510ee14f763cf9f171dcea8b523..60adc91802baa60f84e2bdae3419118c566d7cf4 100644
--- a/device/vr/openvr/openvr_device.cc
+++ b/device/vr/openvr/openvr_device.cc
@@ -76,14 +76,21 @@ std::vector<float> HmdMatrix34ToWebVRTransformMatrix(
 
 namespace device {
 
-OpenVRDevice::OpenVRDevice() {}
+OpenVRDevice::OpenVRDevice() : weak_ptr_factory_(this) {}
 OpenVRDevice::~OpenVRDevice() {}
 
 void OpenVRDevice::CreateVRDisplayInfo(
     const base::Callback<void(mojom::VRDisplayInfoPtr)>& on_created) {
-  vr::EVRInitError init_error;
+  // Initialize init_error with success.
+  vr::EVRInitError init_error = vr::VRInitError_None;
+
+  // vr_system here could be used as openvr device initialization or update
+  // device info.
   auto vr_system =

[nhu, 2017/04/25 00:52:19]

In https://codereview.chromium.org/2825203004/, we consolidated the VR_Init to
OpenVRDeviceProvider to avoid multiple initializations. Will you follow that
approach? billorr@, any thoughts?

-      vr::VR_Init(&init_error, vr::EVRApplicationType::VRApplication_Scene);
+      render_loop_ == nullptr
+          ? vr::VR_Init(&init_error,
+                        vr::EVRApplicationType::VRApplication_Scene)
+          : render_loop_->GetVRSystem();
 
   if (init_error != vr::VRInitError_None) {
     LOG(ERROR) << vr::VR_GetVRInitErrorAsEnglishDescription(init_error);
@@ -91,6 +98,12 @@ void OpenVRDevice::CreateVRDisplayInfo(
     return;
   }
 
+  if (vr_system == nullptr) {
+    LOG(ERROR) << "OpenVRRenderLoop failed to return valid IVRSystem pointer";
+    on_created.Run(nullptr);
+    return;
+  }
+
   mojom::VRDisplayInfoPtr device = mojom::VRDisplayInfo::New();
   device->index = id();
   device->displayName =
@@ -147,7 +160,14 @@ void OpenVRDevice::CreateVRDisplayInfo(
     device->stageParameters->sizeZ = 0.0f;
   }
 
-  render_loop_ = std::make_unique<OpenVRRenderLoop>(vr_system);
+  // If it is first initialization, OpenVRRenderLoop instance need to be
+  // careated and callback need to be registed.
+  if (!render_loop_) {
+    render_loop_ = std::make_unique<OpenVRRenderLoop>(vr_system);
+
+    render_loop_->RegistPollingEventCallback(base::Bind(
+        &OpenVRDevice::OnPollingEvent, weak_ptr_factory_.GetWeakPtr()));
+  }
 
   on_created.Run(std::move(device));
 }
@@ -179,6 +199,23 @@ void OpenVRDevice::UpdateLayerBounds(int16_t frame_index,
   // We don't support presentation currently, so don't do anything.
 }
 
+// TODO(shaobo): OnConnect and OnDisconnect need to be added to VrDisplayClient
+// in vr_service.mojom
+void OpenVRDevice::OnPollingEvent(OpenVRDevice::VREvent event) {
+  switch (event) {
+    case OpenVRDevice::VREvent::CONNECTED:
+    case OpenVRDevice::VREvent::DISCONNECTED:
+      break;
+
+    case OpenVRDevice::VREvent::CHANGED:
+      OnChanged();
+      break;
+
+    default:
+      break;
+  }
+}
+
 void OpenVRDevice::GetVRVSyncProvider(mojom::VRVSyncProviderRequest request) {
   render_loop_->Bind(std::move(request));
 }
@@ -238,11 +275,73 @@ device::mojom::VRPosePtr OpenVRDevice::OpenVRRenderLoop::getPose() {
   return std::move(pose);
 }
 
+// TODO(shaobo) : Expose pointer directly will increase the risk that behaviour
+// out of OpenVRRenderLoop will affect OpenVRRenderLoop. Need to fix it.
+vr::IVRSystem* OpenVRDevice::OpenVRRenderLoop::GetVRSystem() {
+  return vr_system_;
+}
+
+// Only deal with event which will cause displayInfo changed now.
+void OpenVRDevice::OpenVRRenderLoop::PollEvents() {
+  if (!vr_system_ || on_polling_event_.is_null())
+    return;
+
+  vr::VREvent_t event;
+  bool is_changed = false;
+  while (vr_system_->PollNextEvent(&event, sizeof(event))) {
+    if (event.trackedDeviceIndex != vr::k_unTrackedDeviceIndex_Hmd &&
+        event.trackedDeviceIndex != vr::k_unTrackedDeviceIndexInvalid) {
+      continue;
+    }
+
+    switch (event.eventType) {
+      case vr::VREvent_TrackedDeviceActivated:
+        on_polling_event_.Run(OpenVRDevice::VREvent::CONNECTED);
+        break;
+
+      case vr::VREvent_TrackedDeviceDeactivated:
+        on_polling_event_.Run(OpenVRDevice::VREvent::DISCONNECTED);
+        break;
+
+      case vr::VREvent_TrackedDeviceUpdated:
+      case vr::VREvent_IpdChanged:
+      case vr::VREvent_ChaperoneDataHasChanged:
+      case vr::VREvent_ChaperoneSettingsHaveChanged:
+      case vr::VREvent_ChaperoneUniverseHasChanged:
+        is_changed = true;
+        break;
+
+      default:
+        break;
+    }
+  }
+
+  if (is_changed) {
+    on_polling_event_.Run(OpenVRDevice::VREvent::CHANGED);
+  }
+}
+
+// Regist a callback function to deal with system event.
+void OpenVRDevice::OpenVRRenderLoop::RegistPollingEventCallback(
+    const base::Callback<void(OpenVRDevice::VREvent)>& onPollingEvent) {
+  if (onPollingEvent.is_null())
+    return;
+
+  on_polling_event_ = onPollingEvent;
+}
+
+void OpenVRDevice::OpenVRRenderLoop::UnregistPollingEventCallback() {
+  on_polling_event_.Reset();
+}
+
 void OpenVRDevice::OpenVRRenderLoop::GetVSync(
     const mojom::VRVSyncProvider::GetVSyncCallback& callback) {
   static int16_t next_frame = 0;
   int16_t frame = next_frame++;
 
+  // VSync could be used as a signal to poll event.
+  PollEvents();
+
   // TODO(BillOrr): Give real values when VSync loop is hooked up.  This is the
   // presentation time for the frame. Just returning a default value for now
   // since we don't have VSync hooked up.