Build key map DomCodeToKey() for Windows

ui/events/keycodes/key_map_win.h

+// Copyright (c) 2016 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_EVENTS_KEYCODES_KEY_MAP_WIN_H_
+#define UI_EVENTS_KEYCODES_KEY_MAP_WIN_H_
+
+#include <windows.h>
+
+#include <unordered_map>
+
+#include "base/hash.h"
+#include "ui/events/events_base_export.h"
+#include "ui/events/keycodes/dom/dom_key.h"
+#include "ui/events/keycodes/keyboard_codes_win.h"
+
+namespace ui {
+
+enum class DomCode;
+
+typedef std::unordered_map<std::pair<int /*DomCode*/, int /*EventFlags*/>,
+                           DomKey,
+                           base::IntPairHash<std::pair<int, int>>>
+    KeyMap;

[chongz, 2016/02/10 01:25:10]

Currently only store DomCode+flags => DomKey, will add DomCode+flags =>
KeyboardCode when we actually need it.

+
+class EVENTS_BASE_EXPORT WindowsKeyMap {
+ public:
+  // Create and load key map table with specified keyboard layout.
+  explicit WindowsKeyMap(HKL layout) : keyboard_layout_(0) {
+    UpdateLayout(layout);
+  }
+
+  // Convert a DomCode + flags to a DomKey for layout specified in constructor.
+  DomKey DomCodeAndFlagsToKey(DomCode code, int flags /*EventFlags*/) const;
+
+  // Convert a DomCode + flags to a DomKey using the layout for current thread.
+  // Will load/update key map table in first call or when layout has changed.
+  static DomKey CodeAndFlagsToDomKey(DomCode code, int flags /*EventFlags*/);

[chongz, 2016/02/10 01:25:10]

I'm not sure how to name the above two functions... They are doing the similar
thing but one is static?

[dtapuska, 2016/02/10 21:56:34]

Personally I'd name it DomCodeAndFlagsToDomKey
and DomCodeAndFlagsToDomKeyStatic

+
+ private:
+  WindowsKeyMap() : keyboard_layout_(0) {}
+
+  void UpdateLayout(HKL layout);
+
+  HKL keyboard_layout_;
+  KeyMap key_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowsKeyMap);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_KEYCODES_KEY_MAP_WIN_H_