Plumbing through more WebVR presentation code

device/vr/android/gvr/gvr_delegate.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/android/gvr/gvr_delegate.h"
+
+#include "base/logging.h"
+#include "base/memory/singleton.h"
+
+namespace device {
+
+GvrDelegateManager* GvrDelegateManager::GetInstance() {
+  return base::Singleton<GvrDelegateManager>::get();
+}
+
+GvrDelegateManager::GvrDelegateManager() : delegate_(nullptr) {}
+
+GvrDelegateManager::~GvrDelegateManager() {}
+
+void GvrDelegateManager::AddClient(GvrDelegateClient* client) {
+  clients_.push_back(client);
+
+  if (delegate_)
+    client->OnDelegateInitialized(delegate_);
+}
+
+void GvrDelegateManager::RemoveClient(GvrDelegateClient* client) {
+  clients_.erase(std::remove(clients_.begin(), clients_.end(), client),
+                 clients_.end());
+}
+
+void GvrDelegateManager::Initialize(GvrDelegate* delegate) {
+  // Don't initialize the delegate manager twice.
+  DCHECK(!delegate_);
+
+  delegate_ = delegate;
+
+  for (const auto& client : clients_)
+    client->OnDelegateInitialized(delegate_);
+}
+
+void GvrDelegateManager::Shutdown() {
+  if (!delegate_)
+    return;
+
+  delegate_ = nullptr;
+
+  for (const auto& client : clients_)
+    client->OnDelegateShutdown();
+}
+
+}  // namespace device