Adding Chrome-side WebVR interface

content/browser/vr/vr_service_impl.h

+// 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.
+
+#ifndef CONTENT_BROWSER_VR_VR_SERVICE_IMPL_H_
+#define CONTENT_BROWSER_VR_VR_SERVICE_IMPL_H_
+
+#include <vector>
+#include "base/compiler_specific.h"
+#include "content/browser/vr/vr_device_manager.h"
+#include "content/common/vr_service.mojom.h"
+
+namespace content {
+
+class VRDeviceManager;
+
+class VRServiceImpl : public mojo::InterfaceImpl<VRService> {

[Ken Rockot(use gerrit already), 2015/05/31 23:43:47]

InterfaceImpl is deprecated, so please don't use it. You can implement VRService
directly, and then there are a few options for how to bind |request| to your
impl: you can use a mojo::Binding, or a mojo::StrongBinding.

A StrongBinding owns its bound impl and deletes the impl when the bound
MessagePipe is closed. Both Binding and StrongBinding allow you to
set_error_handler to some implementation of mojo::ErrorHandler to handle pipe
closing if you have a need for that. In this case a StrongBinding would work
fine and would effectively mirror the same behavior you get with InterfaceImpl.

However... I don't really see why VRDeviceManager and VRServiceImpl have to be
two separate classes. You don't appear to need a different service
implementation for each request, (i.e. your only per-impl state is "am i
registered with the device manager?"). So alternatively you could merge the two
classes and use a single mojo::WeakBindingSet<VRService> (defined in
//mojo/common/weak_binding_set.h) to bind all incoming requests to a lazy
singleton instance.

To get the same ref-counting behavior as you have now (i.e. cleaning up the
singleton when the last connection closes), you would need to add an accessor to
WeakBindingSet to test if the bindings set is empty (that really should exist; I
guess nobody's needed it yet). Then in addition to VRService you'd also
implement mojo::ErrorHandler and set yourself as the error handler for the
WeakBindingSet; your OnConnectionError impl would delete |this| if the
WeakBindingSet is empty.

+ public:
+  static void Create(mojo::InterfaceRequest<VRService> request);
+
+ protected:
+  VRServiceImpl();
+  ~VRServiceImpl() override;
+
+ private:
+  // Returns the VRDeviceManager singleton.
+  VRDeviceManager* GetDeviceManager();
+
+  void GetDevices(const GetDevicesCallback& callback) override;
+
+  void GetSensorState(uint32_t index,
+                      const GetSensorStateCallback& callback) override;
+
+  void ResetSensor(uint32_t index) override;
+
+  bool registered_with_device_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(VRServiceImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_VR_VR_SERVICE_IMPL_H_