Refactors DeviceOrientation to make it more extensible

content/browser/device_orientation/orientation.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/orientation.h"
+
+namespace device_orientation {
+
+DeviceData* Orientation::Clone() const {
+   Orientation* orientation = new Orientation();
+   orientation->device_data_type_ = DeviceData::kDeviceOrientationData;
+   orientation->alpha_ = alpha_;
+   orientation->beta_ = beta_;
+   orientation->gamma_ = gamma_;
+   orientation->absolute_ = absolute_;
+   orientation->can_provide_alpha_ = can_provide_alpha_;
+   orientation->can_provide_beta_ = can_provide_beta_;
+   orientation->can_provide_gamma_ = can_provide_gamma_;
+   orientation->can_provide_absolute_ = can_provide_absolute_;
+   return orientation;
+}
+
+bool Orientation::IsEmpty() const {
+  return !can_provide_alpha_ && !can_provide_beta_ && !can_provide_gamma_
+      && !can_provide_absolute_;
+}
+
+// Returns true if two orientations are considered different enough that
+// observers should be notified of the new orientation.
+bool Orientation::SignificantlyDifferentFrom(
+    const DeviceData& other_device_data) {
+  const Orientation& other_orientation =
+      static_cast<const Orientation&>(other_device_data);
+
+  return IsElementSignificantlyDifferent(can_provide_alpha_,
+                                         other_orientation.can_provide_alpha(),
+                                         alpha_,
+                                         other_orientation.alpha()) ||
+        IsElementSignificantlyDifferent(can_provide_beta_,
+                                        other_orientation.can_provide_beta(),
+                                        beta_,
+                                        other_orientation.beta()) ||
+        IsElementSignificantlyDifferent(can_provide_gamma_,
+                                        other_orientation.can_provide_gamma(),
+                                        gamma_,
+                                        other_orientation.gamma()) ||
+        (can_provide_absolute_ != other_orientation.can_provide_absolute() ||
+         absolute_ != other_orientation.absolute());
+}
+
+};  // namespace device_orientation