Refactors DeviceOrientation to make it more extensible

content/browser/device_orientation/device_data.h

+// 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.
+
+#ifndef CONTENT_BROWSER_DEVICE_ORIENTATION_DEVICE_DATA_H_
+#define CONTENT_BROWSER_DEVICE_ORIENTATION_DEVICE_DATA_H_
+
+#include <cmath>

[bulach, 2012/07/12 10:43:27]

nit: best to move this (and the method implementation) to the cc file..

[aousterh, 2012/07/12 17:13:57]

Done.

+
+namespace device_orientation {

[bulach, 2012/07/12 10:43:27]

nit: add a \n here..

[aousterh, 2012/07/12 17:13:57]

Done.

+class DeviceData {
+ public:
+  enum DeviceDataType {

[bulach, 2012/07/12 10:43:27]

nit: since it's already scoped to DeviceData, it'd probably be clearer to name
this just Type..

[aousterh, 2012/07/12 17:13:57]

Done.

+    kDeviceOrientationData,

[bulach, 2012/07/12 10:43:27]

nit: also, the enum values are normally named as k${ENUM_NAME}Value..

so these would be either kDeviceDataTypeOrientation, or if you agree with the
above, just kTypeOrientation.

[aousterh, 2012/07/12 17:13:57]

Done.

+    kNumberOfDeviceDataTypes
+  };
+  virtual ~DeviceData() {}
+
+  virtual DeviceData* Clone() const = 0;
+  virtual bool IsEmpty() const = 0;
+  virtual bool SignificantlyDifferentFrom(const DeviceData& other) = 0;
+
+  static bool IsElementSignificantlyDifferent(bool can_provide_element1,

[bulach, 2012/07/12 10:43:27]

nit: as above, probably best to move this to the .cc file to simplify the API..

[aousterh, 2012/07/12 17:13:57]

Done.

+      bool can_provide_element2, double element1, double element2) {
+    const double kThreshold = 0.1;
+
+    if (can_provide_element1 != can_provide_element2)
+      return true;
+    if (can_provide_element1 && std::fabs(element1 - element2) >= kThreshold)
+      return true;
+    return false;
+  }
+};
+
+}  // namespace device_orientation
+
+#endif  // CONTENT_BROWSER_DEVICE_ORIENTATION_DEVICE_DATA_H_