--- a/widget/windows/KeyboardLayout.cpp
+++ b/widget/windows/KeyboardLayout.cpp
@@ -12,18 +12,22 @@
 #include "nsToolkit.h"
 #include "nsQuickSort.h"
 #include "nsAlgorithm.h"
 #include "nsGUIEvent.h"
 #include "nsUnicharUtils.h"
 #include "WidgetUtils.h"
 #include "WinUtils.h"
 #include "nsWindowDbg.h"
+#include "nsServiceManagerUtils.h"
 
 #include "nsIDOMKeyEvent.h"
+#include "nsIIdleServiceInternal.h"
+
+#include "npapi.h"
 
 #include <windows.h>
 #include <winuser.h>
 #include <algorithm>
 
 #ifndef WINABLEAPI
 #include <winable.h>
 #endif
@@ -660,38 +664,69 @@ NativeKey::InitKeyEvent(nsKeyEvent& aKey
 {
   nsIntPoint point(0, 0);
   mWidget->InitEvent(aKeyEvent, &point);
   aKeyEvent.mKeyNameIndex = mKeyNameIndex;
   aKeyEvent.location = GetKeyLocation();
   aModKeyState.InitInputEvent(aKeyEvent);
 }
 
+bool
+NativeKey::DispatchKeyEvent(nsKeyEvent& aKeyEvent,
+                            const MSG* aMsgSentToPlugin) const
+{
+  KeyboardLayout::NotifyIdleServiceOfUserActivity();
+
+  NPEvent pluginEvent;
+  if (aMsgSentToPlugin &&
+      mWidget->GetInputContext().mIMEState.mEnabled == IMEState::PLUGIN) {
+    pluginEvent.event = aMsgSentToPlugin->message;
+    pluginEvent.wParam = aMsgSentToPlugin->wParam;
+    pluginEvent.lParam = aMsgSentToPlugin->lParam;
+    aKeyEvent.pluginEvent = static_cast<void*>(&pluginEvent);
+  }
+
+  return mWidget->DispatchWindowEvent(&aKeyEvent);
+}
+
 /*****************************************************************************
  * mozilla::widget::KeyboardLayout
  *****************************************************************************/
 
 KeyboardLayout* KeyboardLayout::sInstance = nullptr;
+nsIIdleServiceInternal* KeyboardLayout::sIdleService = nullptr;
 
 // static
 KeyboardLayout*
 KeyboardLayout::GetInstance()
 {
   if (!sInstance) {
     sInstance = new KeyboardLayout();
+    nsCOMPtr<nsIIdleServiceInternal> idleService =
+      do_GetService("@mozilla.org/widget/idleservice;1");
+    // The refcount will be decreased at shutting down.
+    sIdleService = idleService.forget().get();
   }
   return sInstance;
 }
 
 // static
 void
 KeyboardLayout::Shutdown()
 {
   delete sInstance;
   sInstance = nullptr;
+  NS_IF_RELEASE(sIdleService);
+}
+
+// static
+void
+KeyboardLayout::NotifyIdleServiceOfUserActivity()
+{
+  sIdleService->ResetIdleTimeOut(0);
 }
 
 KeyboardLayout::KeyboardLayout() :
   mKeyboardLayout(0), mIsOverridden(false),
   mIsPendingToRestoreKeyboardLayout(false)
 {
   mDeadKeyTableListHead = nullptr;
 

--- a/widget/windows/KeyboardLayout.h
+++ b/widget/windows/KeyboardLayout.h
@@ -29,16 +29,17 @@
 #define VK_OEM_4                0xDB
 #define VK_OEM_5                0xDC
 #define VK_OEM_6                0xDD
 #define VK_OEM_7                0xDE
 #define VK_OEM_8                0xDF
 #define VK_OEM_102              0xE2
 #define VK_OEM_CLEAR            0xFE
 
+class nsIIdleServiceInternal;
 struct nsModifierKeyState;
 
 namespace mozilla {
 namespace widget {
 
 class KeyboardLayout;
 
 class ModifierKeyState {
@@ -318,16 +319,23 @@ public:
    */
   void InitKeyEvent(nsKeyEvent& aKeyEvent,
                     const ModifierKeyState& aModKeyState) const;
   void InitKeyEvent(nsKeyEvent& aKeyEvent) const
   {
     InitKeyEvent(aKeyEvent, mModKeyState);
   }
 
+  /**
+   * Dispatches the key event.  Returns true if the event is consumed.
+   * Otherwise, false.
+   */
+  bool DispatchKeyEvent(nsKeyEvent& aKeyEvent,
+                        const MSG* aMsgSentToPlugin = nullptr) const;
+
 private:
   nsRefPtr<nsWindowBase> mWidget;
   HKL mKeyboardLayout;
   uint32_t mDOMKeyCode;
   KeyNameIndex mKeyNameIndex;
 
   // The message which the instance was initialized with.
   UINT mMessage;
@@ -364,16 +372,17 @@ class KeyboardLayout
 {
   friend class NativeKey;
 
 private:
   KeyboardLayout();
   ~KeyboardLayout();
 
   static KeyboardLayout* sInstance;
+  static nsIIdleServiceInternal* sIdleService;
 
   struct DeadKeyTableListEntry
   {
     DeadKeyTableListEntry* next;
     uint8_t data[1];
   };
 
   HKL mKeyboardLayout;
@@ -416,16 +425,17 @@ private:
    * them to the aNativeKey.
    */
   void InitNativeKey(NativeKey& aNativeKey,
                      const ModifierKeyState& aModKeyState);
 
 public:
   static KeyboardLayout* GetInstance();
   static void Shutdown();
+  static void NotifyIdleServiceOfUserActivity();
 
   static bool IsPrintableCharKey(uint8_t aVirtualKey);
 
   /**
    * IsDeadKey() returns true if aVirtualKey is a dead key with aModKeyState.
    * This method isn't stateful.
    */
   bool IsDeadKey(uint8_t aVirtualKey,

--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -3610,32 +3610,16 @@ bool nsWindow::DispatchWindowEvent(nsGUI
   return ConvertStatus(status);
 }
 
 bool nsWindow::DispatchWindowEvent(nsGUIEvent* event, nsEventStatus &aStatus) {
   DispatchEvent(event, aStatus);
   return ConvertStatus(aStatus);
 }
 
-bool nsWindow::DispatchKeyEvent(nsKeyEvent& aKeyEvent,
-                                const MSG *aMsgSentToPlugin)
-{
-  UserActivity();
-
-  NPEvent pluginEvent;
-  if (aMsgSentToPlugin && PluginHasFocus()) {
-    pluginEvent.event = aMsgSentToPlugin->message;
-    pluginEvent.wParam = aMsgSentToPlugin->wParam;
-    pluginEvent.lParam = aMsgSentToPlugin->lParam;
-    aKeyEvent.pluginEvent = (void *)&pluginEvent;
-  }
-
-  return DispatchWindowEvent(&aKeyEvent);
-}
-
 bool nsWindow::DispatchCommandEvent(uint32_t aEventCommand)
 {
   nsCOMPtr<nsIAtom> command;
   switch (aEventCommand) {
     case APPCOMMAND_BROWSER_BACKWARD:
       command = nsGkAtoms::Back;
       break;
     case APPCOMMAND_BROWSER_FORWARD:
@@ -6453,17 +6437,17 @@ LRESULT nsWindow::OnKeyDown(const MSG &a
 
   static bool sRedirectedKeyDownEventPreventedDefault = false;
   bool noDefault;
   if (aFakeCharMessage || !IsRedirectedKeyDownMessage(aMsg)) {
     bool isIMEEnabled = IMEHandler::IsIMEEnabled(mInputContext);
     nsKeyEvent keydownEvent(true, NS_KEY_DOWN, this);
     keydownEvent.keyCode = DOMKeyCode;
     nativeKey.InitKeyEvent(keydownEvent);
-    noDefault = DispatchKeyEvent(keydownEvent, &aMsg);
+    noDefault = nativeKey.DispatchKeyEvent(keydownEvent, &aMsg);
     if (aEventDispatched) {
       *aEventDispatched = true;
     }
 
     // If IMC wasn't associated to the window but is associated it now (i.e.,
     // focus is moved from a non-editable editor to an editor by keydown
     // event handler), WM_CHAR and WM_SYSCHAR shouldn't cause first character
     // inputting if IME is opened.  But then, we should redirect the native
@@ -6778,24 +6762,24 @@ LRESULT nsWindow::OnKeyDown(const MSG &a
         }
       }
 
       nsKeyEvent keypressEvent(true, NS_KEY_PRESS, this);
       keypressEvent.mFlags.Union(extraFlags);
       keypressEvent.charCode = uniChar;
       keypressEvent.alternativeCharCodes.AppendElements(altArray);
       nativeKey.InitKeyEvent(keypressEvent, modKeyState);
-      DispatchKeyEvent(keypressEvent, nullptr);
+      nativeKey.DispatchKeyEvent(keypressEvent);
     }
   } else {
     nsKeyEvent keypressEvent(true, NS_KEY_PRESS, this);
     keypressEvent.mFlags.Union(extraFlags);
     keypressEvent.keyCode = DOMKeyCode;
     nativeKey.InitKeyEvent(keypressEvent, aModKeyState);
-    DispatchKeyEvent(keypressEvent, nullptr);
+    nativeKey.DispatchKeyEvent(keypressEvent);
   }
 
   return noDefault;
 }
 
 // OnKeyUp
 LRESULT nsWindow::OnKeyUp(const MSG &aMsg,
                           const ModifierKeyState &aModKeyState,
@@ -6813,17 +6797,17 @@ LRESULT nsWindow::OnKeyUp(const MSG &aMs
   nativeKey.InitKeyEvent(keyupEvent);
   // Set defaultPrevented of the key event if the VK_MENU is not a system key
   // release, so that the menu bar does not trigger.  This helps avoid
   // triggering the menu bar for ALT key accelerators used in assistive
   // technologies such as Window-Eyes and ZoomText or for switching open state
   // of IME.
   keyupEvent.mFlags.mDefaultPrevented =
     (aMsg.wParam == VK_MENU && aMsg.message != WM_SYSKEYUP);
-  return DispatchKeyEvent(keyupEvent, &aMsg);
+  return nativeKey.DispatchKeyEvent(keyupEvent, &aMsg);
 }
 
 // OnChar
 LRESULT nsWindow::OnChar(const MSG &aMsg,
                          const NativeKey& aNativeKey,
                          const ModifierKeyState &aModKeyState,
                          bool *aEventDispatched,
                          const EventFlags *aExtraFlags)
@@ -6898,17 +6882,17 @@ LRESULT nsWindow::OnChar(const MSG &aMsg
   if (aExtraFlags) {
     keypressEvent.mFlags.Union(*aExtraFlags);
   }
   keypressEvent.charCode = uniChar;
   if (!keypressEvent.charCode) {
     keypressEvent.keyCode = aNativeKey.GetDOMKeyCode();
   }
   aNativeKey.InitKeyEvent(keypressEvent, modKeyState);
-  bool result = DispatchKeyEvent(keypressEvent, &aMsg);
+  bool result = aNativeKey.DispatchKeyEvent(keypressEvent, &aMsg);
   if (aEventDispatched)
     *aEventDispatched = true;
   return result;
 }
 
 void
 nsWindow::SetupKeyModifiersSequence(nsTArray<KeyPair>* aArray, uint32_t aModifiers)
 {

--- a/widget/windows/nsWindow.h
+++ b/widget/windows/nsWindow.h
@@ -190,18 +190,16 @@ public:
    * Event helpers
    */
   virtual bool            DispatchMouseEvent(uint32_t aEventType, WPARAM wParam,
                                              LPARAM lParam,
                                              bool aIsContextMenuKey = false,
                                              int16_t aButton = nsMouseEvent::eLeftButton,
                                              uint16_t aInputSource = nsIDOMMouseEvent::MOZ_SOURCE_MOUSE);
   virtual bool            DispatchWindowEvent(nsGUIEvent*event, nsEventStatus &aStatus);
-  virtual bool            DispatchKeyEvent(nsKeyEvent& aKeyEvent,
-                                           const MSG *aMsgSentToPlugin);
   void                    DispatchPendingEvents();
   bool                    DispatchPluginEvent(UINT aMessage,
                                               WPARAM aWParam,
                                               LPARAM aLParam,
                                               bool aDispatchPendingEvents);
 
   void                    SuppressBlurEvents(bool aSuppress); // Called from nsFilePicker
   bool                    BlurEventsSuppressed();