Refactors DeviceOrientation to make it more extensible

content/browser/device_orientation/observer_delegate.cc

+// Copyright (c) 2012 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 "content/browser/device_orientation/observer_delegate.h"
+
+#include "base/logging.h"
+#include "content/browser/device_orientation/device_data.h"
+#include "content/browser/device_orientation/orientation.h"
+#include "ipc/ipc_sender.h"
+
+namespace device_orientation {
+
+ObserverDelegate::ObserverDelegate(DeviceData::Type device_data_type,
+                                   Provider* provider, int render_view_id,
+                                   IPC::Sender* sender)
+    : Observer(device_data_type),
+      provider_(provider),
+      render_view_id_(render_view_id),
+      sender_(sender) {
+  provider_->AddObserver(this);
+}
+
+ObserverDelegate::~ObserverDelegate() {
+  provider_->RemoveObserver(this);
+}
+
+void ObserverDelegate::OnDeviceDataUpdate(
+    const DeviceData* device_data, DeviceData::Type device_data_type) {
+  scoped_refptr<const DeviceData> new_device_data(device_data);
+  if (!new_device_data.get())
+    new_device_data = EmptyDeviceData(device_data_type);
+
+  sender_->Send(new_device_data->CreateIPCMessage(render_view_id_));
+}
+
+DeviceData* ObserverDelegate::EmptyDeviceData(DeviceData::Type type) {
+  DCHECK(type == DeviceData::kTypeOrientation);
+  return new Orientation();
+}
+
+}  // namespace device_orientation