--- a/gfx/src/nsITheme.h
+++ b/gfx/src/nsITheme.h
@@ -211,22 +211,16 @@ public:
    * Does the nsITheme implementation draw its own focus ring for this widget?
    */
   virtual bool ThemeDrawsFocusForWidget(uint8_t aWidgetType)=0;
   
   /**
     * Should we insert a dropmarker inside of combobox button?
    */
   virtual bool ThemeNeedsComboboxDropmarker()=0;
-
-  /**
-   * Should we hide scrollbars?
-   */
-  virtual bool ShouldHideScrollbars()
-  { return false; }
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsITheme, NS_ITHEME_IID)
 
 // Creator function
 extern nsresult NS_NewNativeTheme(nsISupports *aOuter, REFNSIID aIID, void **aResult);
 
 #endif

--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -3087,22 +3087,16 @@ struct HoveredStateComparator
 };
 
 void
 ScrollFrameHelper::AppendScrollPartsTo(nsDisplayListBuilder*   aBuilder,
                                        const nsDisplayListSet& aLists,
                                        bool                    aCreateLayer,
                                        bool                    aPositioned)
 {
-  nsITheme* theme = mOuter->PresContext()->GetTheme();
-  if (theme &&
-      theme->ShouldHideScrollbars()) {
-    return;
-  }
-
   bool overlayScrollbars =
     LookAndFeel::GetInt(LookAndFeel::eIntID_UseOverlayScrollbars) != 0;
 
   AutoTArray<nsIFrame*, 3> scrollParts;
   for (nsIFrame* kid : mOuter->PrincipalChildList()) {
     if (kid == mScrolledFrame ||
         (kid->IsAbsPosContainingBlock() || overlayScrollbars) != aPositioned) {
       continue;

--- a/widget/windows/WinUtils.cpp
+++ b/widget/windows/WinUtils.cpp
@@ -1764,23 +1764,16 @@ WinUtils::SetupKeyModifiersSequence(nsTA
   for (uint32_t i = 0; i < ArrayLength(sModifierKeyMap); ++i) {
     const uint32_t* map = sModifierKeyMap[i];
     if (aModifiers & map[0]) {
       aArray->AppendElement(KeyPair(map[1], map[2]));
     }
   }
 }
 
-/* static */
-bool
-WinUtils::ShouldHideScrollbars()
-{
-  return false;
-}
-
 // This is in use here and in dom/events/TouchEvent.cpp
 /* static */
 uint32_t
 WinUtils::IsTouchDeviceSupportPresent()
 {
   int32_t touchCapabilities = ::GetSystemMetrics(SM_DIGITIZER);
   return (touchCapabilities & NID_READY) &&
          (touchCapabilities & (NID_EXTERNAL_TOUCH | NID_INTEGRATED_TOUCH));

--- a/widget/windows/WinUtils.h
+++ b/widget/windows/WinUtils.h
@@ -484,18 +484,16 @@ public:
 
   /**
    * Returns true if executable's path is on a network drive.
    */
   static bool RunningFromANetworkDrive();
 
   static void Initialize();
 
-  static bool ShouldHideScrollbars();
-
   /**
    * This function normalizes the input path, converts short filenames to long
    * filenames, and substitutes environment variables for system paths.
    * The resulting output string length is guaranteed to be <= MAX_PATH.
    */
   static bool SanitizePath(const wchar_t* aInputPath, nsAString& aOutput);
 
   /**

--- a/widget/windows/nsNativeThemeWin.cpp
+++ b/widget/windows/nsNativeThemeWin.cpp
@@ -2617,22 +2617,16 @@ nsNativeThemeWin::ThemeGeometryTypeForWi
     case NS_THEME_WINDOW_BUTTON_BOX:
     case NS_THEME_WINDOW_BUTTON_BOX_MAXIMIZED:
       return eThemeGeometryTypeWindowButtons;
     default:
       return eThemeGeometryTypeUnknown;
   }
 }
 
-bool
-nsNativeThemeWin::ShouldHideScrollbars()
-{
-  return WinUtils::ShouldHideScrollbars();
-}
-
 nsITheme::Transparency
 nsNativeThemeWin::GetWidgetTransparency(nsIFrame* aFrame, uint8_t aWidgetType)
 {
   switch (aWidgetType) {
   case NS_THEME_SCROLLBAR_SMALL:
   case NS_THEME_SCROLLBAR:
   case NS_THEME_STATUSBAR:
     // Knowing that scrollbars and statusbars are opaque improves

--- a/widget/windows/nsNativeThemeWin.h
+++ b/widget/windows/nsNativeThemeWin.h
@@ -78,18 +78,16 @@ public:
   virtual bool WidgetAppearanceDependsOnWindowFocus(uint8_t aWidgetType) override;
 
   enum {
     eThemeGeometryTypeWindowButtons = eThemeGeometryTypeUnknown + 1
   };
   virtual ThemeGeometryType ThemeGeometryTypeForWidget(nsIFrame* aFrame,
                                                        uint8_t aWidgetType) override;
 
-  virtual bool ShouldHideScrollbars() override;
-
   nsNativeThemeWin();
 
 protected:
   mozilla::Maybe<nsUXThemeClass> GetThemeClass(uint8_t aWidgetType);
   HANDLE GetTheme(uint8_t aWidgetType);
   nsresult GetThemePartAndState(nsIFrame* aFrame, uint8_t aWidgetType,
                                 int32_t& aPart, int32_t& aState);
   nsresult ClassicGetThemePartAndState(nsIFrame* aFrame, uint8_t aWidgetType,