diff --git a/widget/windows/KeyboardLayout.cpp b/widget/windows/KeyboardLayout.cpp
index 77e970d14357..cd41803b0ef1 100644
--- a/widget/windows/KeyboardLayout.cpp
+++ b/widget/windows/KeyboardLayout.cpp
@@ -388,6 +388,7 @@ NativeKey::NativeKey(nsWindow* aWindow,
   mVirtualKeyCode(0), mOriginalVirtualKeyCode(0)
 {
   KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+  mKeyboardLayout = keyboardLayout->GetLayout();
   mScanCode = WinUtils::GetScanCode(aKeyOrCharMessage.lParam);
   mIsExtended = WinUtils::IsExtendedScanCode(aKeyOrCharMessage.lParam);
   // On WinXP and WinServer2003, we cannot compute the virtual keycode for
@@ -485,9 +486,7 @@ NativeKey::NativeKey(nsWindow* aWindow,
                    "mVirtualKeyCode has been computed already");
 
       // Otherwise, compute the virtual keycode with MapVirtualKeyEx().
-      mVirtualKeyCode = static_cast<uint8_t>(
-        ::MapVirtualKeyEx(GetScanCodeWithExtendedFlag(),
-                          MAPVK_VSC_TO_VK_EX, keyboardLayout->GetLayout()));
+      mVirtualKeyCode = ComputeVirtualKeyCodeFromScanCodeEx();
 
       // The result might be unexpected value due to the scan code is
       // wrong.  For example, any key messages can be generated by
@@ -527,9 +526,8 @@ NativeKey::NativeKey(nsWindow* aWindow,
       if (!canComputeVirtualKeyCodeFromScanCode) {
         break;
       }
-      mVirtualKeyCode = mOriginalVirtualKeyCode = static_cast<uint8_t>(
-        ::MapVirtualKeyEx(GetScanCodeWithExtendedFlag(),
-                          MAPVK_VSC_TO_VK_EX, keyboardLayout->GetLayout()));
+      mVirtualKeyCode = mOriginalVirtualKeyCode =
+        ComputeVirtualKeyCodeFromScanCodeEx();
       break;
     default:
       MOZ_NOT_REACHED("Unsupported message");
@@ -627,6 +625,34 @@ NativeKey::GetKeyLocation() const
   }
 }
 
+uint8_t
+NativeKey::ComputeVirtualKeyCodeFromScanCode() const
+{
+  return static_cast<uint8_t>(
+           ::MapVirtualKeyEx(mScanCode, MAPVK_VSC_TO_VK, mKeyboardLayout));
+}
+
+uint8_t
+NativeKey::ComputeVirtualKeyCodeFromScanCodeEx() const
+{
+  bool VistaOrLater =
+    (WinUtils::GetWindowsVersion() >= WinUtils::VISTA_VERSION);
+  // NOTE: WinXP doesn't support mapping scan code to virtual keycode of
+  //       extended keys.
+  NS_ENSURE_TRUE(!mIsExtended || VistaOrLater, 0);
+  return static_cast<uint8_t>(
+           ::MapVirtualKeyEx(GetScanCodeWithExtendedFlag(), MAPVK_VSC_TO_VK_EX,
+                             mKeyboardLayout));
+}
+
+PRUnichar
+NativeKey::ComputeUnicharFromScanCode() const
+{
+  return static_cast<PRUnichar>(
+           ::MapVirtualKeyEx(ComputeVirtualKeyCodeFromScanCode(),
+                             MAPVK_VK_TO_CHAR, mKeyboardLayout));
+}
+
 /*****************************************************************************
  * mozilla::widget::KeyboardLayout
  *****************************************************************************/
diff --git a/widget/windows/KeyboardLayout.h b/widget/windows/KeyboardLayout.h
index fc641d364659..850485b0ddcd 100644
--- a/widget/windows/KeyboardLayout.h
+++ b/widget/windows/KeyboardLayout.h
@@ -299,7 +299,23 @@ public:
   uint8_t GetVirtualKeyCode() const { return mVirtualKeyCode; }
   uint8_t GetOriginalVirtualKeyCode() const { return mOriginalVirtualKeyCode; }
 
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK.
+   */
+  uint8_t ComputeVirtualKeyCodeFromScanCode() const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK_EX.
+   */
+  uint8_t ComputeVirtualKeyCodeFromScanCodeEx() const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK and MAPVK_VK_TO_CHAR.
+   */
+  PRUnichar ComputeUnicharFromScanCode() const;
+
 private:
+  HKL mKeyboardLayout;
   uint32_t mDOMKeyCode;
   KeyNameIndex mKeyNameIndex;
 
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index fb6703a72506..b1b3d74540e0 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -6892,14 +6892,10 @@ LRESULT nsWindow::OnChar(const MSG &aMsg,
   // that numbers are always passed as such (among others: bugs 50255 and 351310)
   if (uniChar && (modKeyState.IsControl() || modKeyState.IsAlt())) {
     KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
-    UINT virtualKeyCode =
-      ::MapVirtualKeyEx(aNativeKey.GetScanCode(),
-                        MAPVK_VSC_TO_VK, keyboardLayout->GetLayout());
+    UINT virtualKeyCode = aNativeKey.ComputeVirtualKeyCodeFromScanCode();
     UINT unshiftedCharCode =
       virtualKeyCode >= '0' && virtualKeyCode <= '9' ? virtualKeyCode :
-        modKeyState.IsShift() ?
-          ::MapVirtualKeyEx(virtualKeyCode, MAPVK_VK_TO_CHAR,
-                            keyboardLayout->GetLayout()) : 0;
+        modKeyState.IsShift() ? aNativeKey.ComputeUnicharFromScanCode() : 0;
     // ignore diacritics (top bit set) and key mapping errors (char code 0)
     if ((INT)unshiftedCharCode > 0)
       uniChar = unshiftedCharCode;