Reland: [DomKey] Expose Korean special keys on Korean keyboard layout only

ui/events/keycodes/platform_key_map_win.cc

Index: ui/events/keycodes/platform_key_map_win.cc
diff --git a/ui/events/keycodes/platform_key_map_win.cc b/ui/events/keycodes/platform_key_map_win.cc
index 756fabfca5dc72ec6627c38fa04467150b656c83..593e386936dd4167f21ca08105d0024186715185 100644
--- a/ui/events/keycodes/platform_key_map_win.cc
+++ b/ui/events/keycodes/platform_key_map_win.cc
@@ -183,9 +183,6 @@ const struct NonPrintableKeyEntry {
     {VKEY_ALTGR, DomKey::ALT_GRAPH},
     {VKEY_PROCESSKEY, DomKey::PROCESS},
     // VKEY_PACKET - Used to pass Unicode char, considered as printable key.
-
-    // TODO(chongz): Handle Japanese keyboard layout keys 0xF0..0xF5.
-    // https://crbug.com/612694
     {VKEY_ATTN, DomKey::ATTN},
     {VKEY_CRSEL, DomKey::CR_SEL},
     {VKEY_EXSEL, DomKey::EX_SEL},
@@ -197,7 +194,30 @@ const struct NonPrintableKeyEntry {
     {VKEY_OEM_CLEAR, DomKey::CLEAR},
 };
 
-DomKey NonPrintableKeyboardCodeToDomKey(KeyboardCode key_code) {
+// Disambiguates the meaning of certain non-printable keys which have different
+// meanings under different languages, but use the same VKEY code.
+DomKey LanguageSpecificOemKeyboardCodeToDomKey(KeyboardCode key_code,
+                                               HKL layout) {
+  WORD language = LOWORD(layout);
+  WORD primary_language = PRIMARYLANGID(language);
+  if (primary_language == LANG_KOREAN) {
+    switch (key_code) {
+      case VKEY_HANGUL:
+        return DomKey::HANGUL_MODE;
+      case VKEY_HANJA:
+        return DomKey::HANJA_MODE;
+      default:
+        return DomKey::NONE;
+    }
+  }
+  // TODO(chongz): Handle Japanese keyboard layout keys 0xF0..0xF5, VKEY_KANA,
+  // VKEY_KANJI.
+  // https://crbug.com/612694
+  return DomKey::NONE;
+}
+
+DomKey NonPrintableKeyboardCodeToDomKey(KeyboardCode key_code, HKL layout) {
+  // 1. Most |key_codes| have the same meaning regardless of |layout|.
   const NonPrintableKeyEntry* result = std::lower_bound(
       std::begin(kNonPrintableKeyMap), std::end(kNonPrintableKeyMap), key_code,
       [](const NonPrintableKeyEntry& entry, KeyboardCode needle) {
@@ -205,7 +225,8 @@ DomKey NonPrintableKeyboardCodeToDomKey(KeyboardCode key_code) {
       });
   if (result != std::end(kNonPrintableKeyMap) && result->key_code == key_code)
     return result->dom_key;
-  return DomKey::NONE;
+  // 2. Look up a |layout|-specific meaning for |key_code|.
+  return LanguageSpecificOemKeyboardCodeToDomKey(key_code, layout);
 }
 
 void CleanupKeyMapTls(void* data) {
@@ -238,14 +259,10 @@ PlatformKeyMap::~PlatformKeyMap() {}
 
 DomKey PlatformKeyMap::DomKeyFromKeyboardCodeImpl(KeyboardCode key_code,
                                                   int flags) const {
-  DomKey key = NonPrintableKeyboardCodeToDomKey(key_code);
+  DomKey key = NonPrintableKeyboardCodeToDomKey(key_code, keyboard_layout_);
   if (key != DomKey::NONE)
     return key;
 
-  // TODO(chongz): Handle VKEY_KANA/VKEY_HANGUL, VKEY_HANJA/VKEY_KANJI based on
-  // layout.
-  // https://crbug.com/612736
-
   const int flags_to_try[] = {
       // Trying to match Firefox's behavior and UIEvents DomKey guidelines.
       // If the combination doesn't produce a printable character, the key value