--- a/hal/Makefile.in
+++ b/hal/Makefile.in
@@ -39,16 +39,17 @@ DEPTH       = ..
 topsrcdir   = @top_srcdir@
 srcdir      = @srcdir@
 VPATH       = \
   $(srcdir) \
   $(srcdir)/android \
   $(srcdir)/fallback \
   $(srcdir)/sandbox \
   $(srcdir)/linux \
+  $(srcdir)/windows \
   $(NULL)
 
 include $(DEPTH)/config/autoconf.mk
 
 MODULE         = hal
 LIBRARY_NAME   = hal_s
 FORCE_STATIC_LIB = 1
 LIBXUL_LIBRARY = 1
@@ -68,16 +69,18 @@ CPPSRCS = \
 
 ifeq (android,$(MOZ_WIDGET_TOOLKIT))
 CPPSRCS += AndroidHal.cpp
 else ifeq (Linux,$(OS_TARGET))
 CPPSRCS += LinuxHal.cpp
 ifdef MOZ_ENABLE_DBUS
 CPPSRCS += UPowerClient.cpp
 endif
+else ifeq (WINNT,$(OS_TARGET))
+CPPSRCS += WindowsHal.cpp WindowsBattery.cpp
 else
 CPPSRCS += FallbackHal.cpp
 endif
 
 include $(topsrcdir)/config/config.mk
 include $(topsrcdir)/ipc/chromium/chromium-config.mk
 include $(topsrcdir)/config/rules.mk
 

new file mode 100644
--- /dev/null
+++ b/hal/windows/WindowsBattery.cpp
@@ -0,0 +1,236 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is the Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2011
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Makoto Kato <m_kato@ga2.so-net.ne.jp> (Original Author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "Hal.h"
+#include "nsITimer.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/dom/battery/Constants.h"
+
+#include <windows.h>
+
+using namespace mozilla::dom::battery;
+
+namespace mozilla {
+namespace hal_impl {
+
+static nsCOMPtr<nsITimer> sUpdateTimer;
+
+#if MOZ_WINSDK_TARGETVER >= MOZ_NTDDI_LONGHORN
+/* Power Event API is Vista or later */
+typedef HPOWERNOTIFY (WINAPI *REGISTERPOWERSETTINGNOTIFICATION) (HANDLE, LPCGUID, DWORD);
+typedef BOOL (WINAPI *UNREGISTERPOWERSETTINGNOTIFICATION) (HPOWERNOTIFY);
+static REGISTERPOWERSETTINGNOTIFICATION sRegisterPowerSettingNotification = nsnull;
+static UNREGISTERPOWERSETTINGNOTIFICATION sUnregisterPowerSettingNotification = nsnull;
+static HPOWERNOTIFY sPowerHandle = nsnull;
+static HPOWERNOTIFY sCapacityHandle = nsnull;
+static HWND sHWnd = nsnull;
+#endif
+
+
+static bool
+IsVistaOrLater()
+{
+  OSVERSIONINFO info;
+
+  ZeroMemory(&info, sizeof(OSVERSIONINFO));
+  info.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+  GetVersionEx(&info);
+
+  return info.dwMajorVersion >= 6;
+}
+
+static void
+UpdateHandler(nsITimer* aTimer, void* aClosure) {
+  NS_ASSERTION(!IsVistaOrLater(),
+               "We shouldn't call this function for Vista or later version!");
+
+  static hal::BatteryInformation sLastInfo;
+  hal::BatteryInformation currentInfo;
+
+  hal_impl::GetCurrentBatteryInformation(&currentInfo);
+  if (sLastInfo.level() != currentInfo.level() ||
+      sLastInfo.charging() != currentInfo.charging() ||
+      sLastInfo.remainingTime() != currentInfo.remainingTime()) {
+    hal::NotifyBatteryChange(currentInfo);
+    sLastInfo = currentInfo;
+  }
+}
+
+#if MOZ_WINSDK_TARGETVER >= MOZ_NTDDI_LONGHORN
+static
+LRESULT CALLBACK
+BatteryWindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
+  if (msg != WM_POWERBROADCAST || wParam != PBT_POWERSETTINGCHANGE) {
+    return DefWindowProc(hwnd, msg, wParam, lParam);
+  }
+
+  hal::BatteryInformation currentInfo;
+
+  // Since we need update remainingTime, we cannot use LPARAM.
+  hal_impl::GetCurrentBatteryInformation(&currentInfo);
+
+  hal::NotifyBatteryChange(currentInfo);
+  return TRUE;
+}
+#endif
+
+void
+EnableBatteryNotifications()
+{
+#if MOZ_WINSDK_TARGETVER >= MOZ_NTDDI_LONGHORN
+  if (IsVistaOrLater()) {
+    // RegisterPowerSettingNotification is from Vista or later.
+    // Use this API if available.
+    HMODULE hUser32 = GetModuleHandleW(L"USER32.DLL");
+    if (!sRegisterPowerSettingNotification)
+      sRegisterPowerSettingNotification = (REGISTERPOWERSETTINGNOTIFICATION)
+        GetProcAddress(hUser32, "RegisterPowerSettingNotification");
+    if (!sUnregisterPowerSettingNotification)
+      sUnregisterPowerSettingNotification = (UNREGISTERPOWERSETTINGNOTIFICATION)
+        GetProcAddress(hUser32, "UnregisterPowerSettingNotification");
+
+    if (!sRegisterPowerSettingNotification ||
+        !sUnregisterPowerSettingNotification) {
+      NS_ASSERTION(false, "Canot find PowerSettingNotification functions.");
+      return;
+    }
+
+    // Create custom window to watch battery event
+    // If we can get Gecko's window handle, this is unnecessary.
+
+    if (sHWnd == nsnull) {
+      WNDCLASSW wc;
+      HMODULE hSelf = GetModuleHandle(nsnull);
+
+      if (!GetClassInfoW(hSelf, L"MozillaBatteryClass", &wc)) {
+        ZeroMemory(&wc, sizeof(WNDCLASSW));
+        wc.hInstance = hSelf;
+        wc.lpfnWndProc = BatteryWindowProc;
+        wc.lpszClassName = L"MozillaBatteryClass";
+        RegisterClassW(&wc);
+      }
+
+      sHWnd = CreateWindowW(L"MozillaBatteryClass", L"Battery Watcher",
+                            0, 0, 0, 0, 0,
+                            nsnull, nsnull, hSelf, nsnull);
+    }
+
+    if (sHWnd == nsnull) {
+      return;
+    }
+
+    sPowerHandle =
+      sRegisterPowerSettingNotification(sHWnd,
+                                        &GUID_ACDC_POWER_SOURCE,
+                                        DEVICE_NOTIFY_WINDOW_HANDLE);
+    sCapacityHandle =
+      sRegisterPowerSettingNotification(sHWnd,
+                                        &GUID_BATTERY_PERCENTAGE_REMAINING,
+                                        DEVICE_NOTIFY_WINDOW_HANDLE);
+  } else
+#endif
+  {
+    // for Windows 2000 and Windwos XP.  If we remove Windows XP support,
+    // we should remove timer-based power notification
+    sUpdateTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
+    if (sUpdateTimer) {
+      sUpdateTimer->InitWithFuncCallback(UpdateHandler,
+                                         nsnull,
+                                         Preferences::GetInt("dom.battery.timer",
+                                                             30000 /* 30s */),
+                                         nsITimer::TYPE_REPEATING_SLACK);
+    } 
+  }
+}
+
+void
+DisableBatteryNotifications()
+{
+#if MOZ_WINSDK_TARGETVER >= MOZ_NTDDI_LONGHORN
+  if (IsVistaOrLater()) {
+    if (sPowerHandle) {
+      sUnregisterPowerSettingNotification(sPowerHandle);
+      sPowerHandle = nsnull;
+    }
+
+    if (sCapacityHandle) {
+      sUnregisterPowerSettingNotification(sCapacityHandle);
+      sCapacityHandle = nsnull;
+    }
+
+    if (sHWnd) {
+      DestroyWindow(sHWnd);
+      sHWnd = nsnull;
+    }
+  } else
+#endif
+  {
+    if (sUpdateTimer) {
+      sUpdateTimer->Cancel();
+      sUpdateTimer = nsnull;
+    }
+  }
+}
+
+void
+GetCurrentBatteryInformation(hal::BatteryInformation* aBatteryInfo)
+{
+  SYSTEM_POWER_STATUS status;
+  if (!GetSystemPowerStatus(&status)) {
+    aBatteryInfo->level() = kDefaultLevel;
+    aBatteryInfo->charging() = kDefaultCharging;
+    aBatteryInfo->remainingTime() = kDefaultRemainingTime;
+    return;
+  }
+
+  aBatteryInfo->level() =
+    status.BatteryLifePercent == 255 ? kDefaultLevel
+                                     : ((double)status.BatteryLifePercent) / 100.0;
+  aBatteryInfo->charging() = (status.ACLineStatus != 0);
+  if (status.ACLineStatus != 0) {
+    aBatteryInfo->remainingTime() =
+      status.BatteryFullLifeTime == (DWORD)-1 ? kUnknownRemainingTime
+                                              : status.BatteryFullLifeTime;
+  } else {
+    aBatteryInfo->remainingTime() =
+      status.BatteryLifeTime == (DWORD)-1 ? kUnknownRemainingTime
+                                          : status.BatteryLifeTime;
+  }
+}
+
+} // hal_impl
+} // mozilla

new file mode 100644
--- /dev/null
+++ b/hal/windows/WindowsHal.cpp
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is the Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2011
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Makoto Kato <m_kato@ga2.so-net.ne.jp> (Original Author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "Hal.h"
+
+namespace mozilla {
+namespace hal_impl {
+
+void
+Vibrate(const nsTArray<uint32>& pattern, const hal::WindowIdentifier &)
+{}
+
+void
+CancelVibrate(const hal::WindowIdentifier &)
+{}
+
+} // hal_impl
+} // mozilla

--- a/ipc/glue/WindowsMessageLoop.cpp
+++ b/ipc/glue/WindowsMessageLoop.cpp
@@ -218,16 +218,17 @@ ProcessOrDeferMessage(HWND hwnd,
     case WM_DISPLAYCHANGE:
     case WM_SHOWWINDOW: // Intentional fall-through.
     case WM_XP_THEMECHANGED: {
       deferred = new DeferredSendMessage(hwnd, uMsg, wParam, lParam);
       break;
     }
 
     case WM_DEVICECHANGE:
+    case WM_POWERBROADCAST:
     case WM_NCACTIVATE: // Intentional fall-through.
     case WM_SETCURSOR: {
       // Friggin unconventional return value...
       res = TRUE;
       deferred = new DeferredSendMessage(hwnd, uMsg, wParam, lParam);
       break;
     }