Add cross-platform API to get the form factor of the device

ui/base/device_form_factor.h

Index: ui/base/device_form_factor.h
diff --git a/ui/base/device_form_factor.h b/ui/base/device_form_factor.h
new file mode 100644
index 0000000000000000000000000000000000000000..c2c21ba602ed5bfa813487d41a20ea266dd69a54
--- /dev/null
+++ b/ui/base/device_form_factor.h
@@ -0,0 +1,16 @@
+// Copyright 2013 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 UI_BASE_DEVICE_FORM_FACTOR_H_
+#define UI_BASE_DEVICE_FORM_FACTOR_H_
+

[Alexei Svitkine (slow), 2013/11/01 18:48:27]

Add "namespace ui {" and "}  // namespace ui" at the end. Here and in the
implementation files.

(Callers will then need to use that prefix - e.g. ui::GetDeviceFormFactor() ==
ui::DEVICE_FORM_FACTOR_DESKTOP).

[yao, 2013/11/04 15:56:19]

Done.

+enum DeviceFormFactor {
+  DEVICE_FORM_FACTOR_DESKTOP = 0,
+  DEVICE_FORM_FACTOR_PHONE = 1,
+  DEVICE_FORM_FACTOR_TABLET = 2
+};
+
+DeviceFormFactor GetDeviceFormFactor();
+
+#endif  // UI_BASE_DEVICE_FORM_FACTOR_H_