[KeyboardMap] Fix handling of yen and won keys

With Windows Japanese and Korean layouts, the OS returns
duplicate values so it appears that multiple keys return
the '\' char.

It should return the currency symbol (yen or won) instead
of the '\', but J and K codepage history means that
Windows will conveniently (or not) map these characters
to the backslash.

See:
https://web.archive.org/web/20131023080358/http://blogs.msdn.com:80/b/michkap/archive/2005/09/17/469941.aspx
for some history/background.

Bug: 910649
Change-Id: If27e4e46959fccd3da292365c521d7f3c4bb2a9b
Reviewed-on: https://chromium-review.googlesource.com/c/1356875Reviewed-by: Joe Downing <joedow@chromium.org>
Commit-Queue: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612789}

ui/events/keycodes/dom/dom_keyboard_layout_map_win.cc

@@ -102,20 +102,37 @@ ui::DomKey DomKeyboardLayoutMapWin::GetDomKeyFromDomCodeForLayout(
       ::ToUnicodeEx(virtual_key_code, scan_code, keyboard_state, char_buffer,
                     base::size(char_buffer), /*wFlags=*/0, keyboard_layout);
 
-  if (key_type == 1)
-    return ui::DomKey::FromCharacter(char_buffer[0]);
-  if (key_type == -1)
-    return ui::DomKey::DeadKeyFromCombiningCharacter(char_buffer[0]);
-
-  // Special case for Backquote on Japanese keyboard layout.
+  // Handle special cases for Japanese keyboard layout.
+  if (0x04110411 == reinterpret_cast<unsigned int>(keyboard_layout)) {
+    // Fix value for Japanese yen currency symbol.
+    // Windows returns '\' for both IntlRo and IntlYen, even though IntlYen
+    // should be the yen symbol.
+    if (dom_code == ui::DomCode::INTL_YEN)
+      return ui::DomKey::FromCharacter(0x00a5);  // Japanese yen symbol.
+
+    // Special case for Backquote.
     // Technically, this layout is not completely ASCII-capable because the
-  // Backquote key is used as a IME function key (hankaku/zenkaku) and is thus
-  // not a printable key. However, other than this key, it is a perfectly
+    // Backquote key is used as an IME function key (hankaku/zenkaku) and is
+    // thus not a printable key. However, other than this key, it is a perfectly
     // usable ASCII-capable layout and it matches the values printed on the
     // keyboard, so we have special handling to allow this key.
-  if (dom_code == ui::DomCode::BACKQUOTE &&
-      0x04110411 == reinterpret_cast<unsigned int>(keyboard_layout))
+    if (dom_code == ui::DomCode::BACKQUOTE)
       return ui::DomKey::ZENKAKU_HANKAKU;
+  }
+
+  // Handle special cases for Korean keyboard layout.
+  if (0x04120412 == reinterpret_cast<unsigned int>(keyboard_layout)) {
+    // Fix value for Korean won currency symbol.
+    // Windows returns '\' for both Backslash and IntlBackslash, even though
+    // IntlBackslash should be the won symbol.
+    if (dom_code == ui::DomCode::INTL_BACKSLASH)
+      return ui::DomKey::FromCharacter(0x20a9);  // Korean won symbol.
+  }
+
+  if (key_type == 1)
+    return ui::DomKey::FromCharacter(char_buffer[0]);
+  if (key_type == -1)
+    return ui::DomKey::DeadKeyFromCombiningCharacter(char_buffer[0]);
 
   return ui::DomKey::NONE;
 }