Fixes 2D-to-WebVR site transitions when browsing in VR.

device/vr/vr_service_impl.cc

 // Copyright 2016 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.
 
 #include "device/vr/vr_service_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "device/vr/vr_device.h"
 #include "device/vr/vr_device_manager.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 
 namespace device {
 
-VRServiceImpl::VRServiceImpl() : listening_for_activate_(false) {}
+VRServiceImpl::VRServiceImpl()
+    : listening_for_activate_(false), weak_ptr_factory_(this) {}
 
 VRServiceImpl::~VRServiceImpl() {
   // Destroy VRDisplay before calling RemoveService below. RemoveService might
   // implicitly trigger destory VRDevice which VRDisplay needs to access in its
   // dtor.
   displays_.clear();
   VRDeviceManager::GetInstance()->RemoveService(this);
 }
 
 void VRServiceImpl::Create(mojo::InterfaceRequest<mojom::VRService> request) {
   mojo::MakeStrongBinding(base::MakeUnique<VRServiceImpl>(),
                           std::move(request));
 }
 
-// Gets a VRDisplayPtr unique to this service so that the associated page can
-// communicate with the VRDevice.
-VRDisplayImpl* VRServiceImpl::GetVRDisplayImpl(VRDevice* device) {
-  auto it = displays_.find(device);
-  if (it != displays_.end())
-    return it->second.get();
-
-  VRDisplayImpl* display_impl = new VRDisplayImpl(device, this);
-  displays_[device] = base::WrapUnique(display_impl);
-  return display_impl;
-}
-
-void VRServiceImpl::RemoveDevice(VRDevice* device) {
-  displays_.erase(device);
-}
-
 void VRServiceImpl::SetClient(mojom::VRServiceClientPtr service_client,
                               const SetClientCallback& callback) {
   DCHECK(!client_.get());
   client_ = std::move(service_client);
   VRDeviceManager* device_manager = VRDeviceManager::GetInstance();
   // Once a client has been connected AddService will force any VRDisplays to
   // send OnConnected to it so that it's populated with the currently active
   // displays. Thereafer it will stay up to date by virtue of listening for new
   // connected events.
   device_manager->AddService(this);
   callback.Run(device_manager->GetNumberOfConnectedDevices());
 }
 
+void VRServiceImpl::ConnectDevice(VRDevice* device) {

[amp, 2017/03/13 22:26:05]

There still seems to be a mismatch between displays and devices.  When do we use
one term vs the other?

[tiborg, 2017/03/13 23:00:58]

I agree, it's a bit confusing. Currently a display is a representation of a
device in the current WebVR session. So, if there are multiple sessions, there
will be a display in each session for each device. 

[bajones, 2017/03/13 23:04:57]

Oh, and just to make things MORE confusing we're gonna be changing some names in
the upcoming spec version: https://github.com/w3c/webvr/issues/192 (The primary
troublemaker there being Display->Device.)

I'm sorry. Really just so very sorry. :(

[amp, 2017/03/14 17:05:50]

Yea let's handle cleaning this up in a future change, I think I'm starting to
understand how they all work together, but it should be a lot easier for anyone
who looks at the code for the first time to be able to figure out what is going
on.

+  DCHECK(displays_.count(device) == 0);
+  // TODO(crbug/701027): make sure that client_ is never null by initializing it
+  // in the constructor.
+  DCHECK(client_);
+  base::Callback<void(mojom::VRDisplayInfoPtr)> onCreated =
+      base::Bind(&VRServiceImpl::OnVRDisplayInfoCreated,
+                 weak_ptr_factory_.GetWeakPtr(), device);
+  device->CreateVRDisplayInfo(onCreated);
+}
+
 void VRServiceImpl::SetListeningForActivate(bool listening) {
   listening_for_activate_ = listening;
   VRDeviceManager* device_manager = VRDeviceManager::GetInstance();
   device_manager->ListeningForActivateChanged(listening);
 }
 
+// Creates a VRDisplayPtr unique to this service so that the associated page can
+// communicate with the VRDevice.
+void VRServiceImpl::OnVRDisplayInfoCreated(
+    VRDevice* device,
+    mojom::VRDisplayInfoPtr display_info) {
+  displays_[device] = base::MakeUnique<VRDisplayImpl>(
+      device, this, client_.get(), std::move(display_info));
+}
+
+VRDisplayImpl* VRServiceImpl::GetVRDisplayImpl(VRDevice* device) {
+  auto it = displays_.find(device);
+  return (it == displays_.end()) ? nullptr : it->second.get();
+}
+
 }  // namespace device