Move GetCharacterFromKeyCode from views::KeyEvent to ui/base/keycodes/keyboard_code_conversion.h.

ui/base/keycodes/keyboard_code_conversion.h

+// Copyright (c) 2011 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_KEYCODES_KEYBOARD_CODE_CONVERSION_H_
+#define UI_BASE_KEYCODES_KEYBOARD_CODE_CONVERSION_H_
+
+#include "base/basictypes.h"
+#include "ui/base/keycodes/keyboard_codes.h"
+#include "ui/base/ui_export.h"
+
+namespace ui {
+
+// A helper function to get the character generated by a key event in a
+// platform independent way. It supports control characters as well.
+// It assumes a US keyboard layout is used, so it may only be used when there
+// is no native event or no better way to get the character.
+// For example, if a virtual keyboard implementation can only generate key
+// events with key_code and flags information, then there is no way for us to
+// determine the actual character that should be generate by the key. Because
+// a key_code only represents a physical key on the keyboard, it has nothing
+// to do with the actual character printed on that key. In such case, the only
+// thing we can do is to assume that we are using a US keyboard and get the
+// character according to US keyboard layout definition.
+// If a virtual keyboard implementation wants to support other keyboard
+// layouts, that may generate different text for a certain key than on a US
+// keyboard, a special native event object should be introduced to carry extra
+// information to help determine the correct character.
+// Take XKeyEvent as an example, it contains not only keycode and modifier
+// flags but also group and other extra XKB information to help determine the
+// correct character. That's why we can use XLookupString() function to get
+// the correct text generated by a X key event (See how is GetCharacter()
+// implemented in event_x.cc).
+// TODO(suzhe): define a native event object for virtual keyboard. We may need
+// to take the actual feature requirement into account.

[James Su, 2011/11/15 04:00:42]

Looks like this TODO is not valid anymore. I think we can simply remove it.

[Yusuke Sato, 2011/11/15 05:16:51]

Done.

+UI_EXPORT uint16 GetCharacterFromKeyCode(KeyboardCode key_code, int flags);
+
+}  // namespace ui
+
+#endif  // UI_BASE_KEYCODES_KEYBOARD_CODE_CONVERSION_H_