diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 25679f0e7965..95989abed8b0 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -6104,10 +6104,13 @@ nsGlobalWindow::SetFullscreenInternal(FullscreenReason aReason,
       if (aHMD) {
         screen = aHMD->GetScreen();
       }
-      if (aReason == eForFullscreenAPI) {
-        widget->PrepareForDOMFullscreenTransition();
+      if (aReason == eForFullscreenMode) {
+        // If we enter fullscreen for fullscreen mode, we want
+        // the native system behavior.
+        widget->MakeFullScreenWithNativeTransition(aFullScreen, screen);
+      } else {
+        widget->MakeFullScreen(aFullScreen, screen);
       }
-      widget->MakeFullScreen(aFullScreen, screen);
       // The rest of code for switching fullscreen is in nsGlobalWindow::
       // FinishFullscreenChange() which will be called after sizemodechange
       // event is dispatched.
diff --git a/widget/cocoa/nsCocoaWindow.h b/widget/cocoa/nsCocoaWindow.h
index 182d2c6dc6ab..8c049d3c8976 100644
--- a/widget/cocoa/nsCocoaWindow.h
+++ b/widget/cocoa/nsCocoaWindow.h
@@ -285,10 +285,13 @@ class nsCocoaWindow : public nsBaseWidget, public nsPIWidgetCocoa
                                         nsIWidget *aWidget, bool aActivate) override;
     NS_IMETHOD              SetSizeMode(int32_t aMode) override;
     NS_IMETHOD              HideWindowChrome(bool aShouldHide) override;
-    virtual void            PrepareForDOMFullscreenTransition() override;
+
     void EnteredFullScreen(bool aFullScreen, bool aNativeMode = true);
-    inline bool ShouldToggleNativeFullscreen(bool aFullScreen);
-    NS_IMETHOD              MakeFullScreen(bool aFullScreen, nsIScreen* aTargetScreen = nullptr) override;
+    NS_IMETHOD MakeFullScreen(
+      bool aFullScreen, nsIScreen* aTargetScreen = nullptr) override final;
+    NS_IMETHOD MakeFullScreenWithNativeTransition(
+      bool aFullScreen, nsIScreen* aTargetScreen = nullptr) override final;
+
     NS_IMETHOD              Resize(double aWidth, double aHeight, bool aRepaint) override;
     NS_IMETHOD              Resize(double aX, double aY, double aWidth, double aHeight, bool aRepaint) override;
     NS_IMETHOD              GetClientBounds(nsIntRect &aRect) override;
@@ -385,6 +388,10 @@ class nsCocoaWindow : public nsBaseWidget, public nsPIWidgetCocoa
   nsresult             DoResize(double aX, double aY, double aWidth, double aHeight,
                                 bool aRepaint, bool aConstrainToCurrentScreen);
 
+  inline bool ShouldToggleNativeFullscreen(bool aFullScreen,
+                                           bool aUseSystemTransition);
+  nsresult DoMakeFullScreen(bool aFullScreen, bool aUseSystemTransition);
+
   virtual already_AddRefed<nsIWidget>
   AllocateChildPopupWidget() override
   {
@@ -414,10 +421,6 @@ class nsCocoaWindow : public nsBaseWidget, public nsPIWidgetCocoa
   bool                 mInFullScreenMode;
   bool                 mInFullScreenTransition; // true from the request to enter/exit fullscreen
                                                 // (MakeFullScreen() call) to EnteredFullScreen()
-  // We are in transition to/from DOM Fullscreen.
-  // XXX The transition is not implemented yet. This is currently only
-  // used to distinguish between DOM fullscreen and fullscreen mode.
-  bool                 mInDOMFullscreenTransition;
   bool                 mModal;
 
   // Only true on 10.7+ if SetShowsFullScreenButton(true) is called.
diff --git a/widget/cocoa/nsCocoaWindow.mm b/widget/cocoa/nsCocoaWindow.mm
index eb9626fa3626..2dbb22779773 100644
--- a/widget/cocoa/nsCocoaWindow.mm
+++ b/widget/cocoa/nsCocoaWindow.mm
@@ -108,7 +108,6 @@ static void RollUpPopups()
 , mSheetNeedsShow(false)
 , mInFullScreenMode(false)
 , mInFullScreenTransition(false)
-, mInDOMFullscreenTransition(false)
 , mModal(false)
 , mSupportsNativeFullScreen(false)
 , mInNativeFullScreenMode(false)
@@ -1266,11 +1265,6 @@ static unsigned int WindowMaskForBorderStyle(nsBorderStyle aBorderStyle)
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
 }
 
-void nsCocoaWindow::PrepareForDOMFullscreenTransition()
-{
-  mInDOMFullscreenTransition = true;
-}
-
 void nsCocoaWindow::EnteredFullScreen(bool aFullScreen, bool aNativeMode)
 {
   mInFullScreenTransition = false;
@@ -1284,7 +1278,9 @@ static unsigned int WindowMaskForBorderStyle(nsBorderStyle aBorderStyle)
   }
 }
 
-inline bool nsCocoaWindow::ShouldToggleNativeFullscreen(bool aFullScreen)
+inline bool
+nsCocoaWindow::ShouldToggleNativeFullscreen(bool aFullScreen,
+                                            bool aUseSystemTransition)
 {
   if (!mSupportsNativeFullScreen) {
     // If we cannot use native fullscreen, don't touch it.
@@ -1294,17 +1290,30 @@ static unsigned int WindowMaskForBorderStyle(nsBorderStyle aBorderStyle)
     // If we are using native fullscreen, go ahead to exit it.
     return true;
   }
-  if (mInDOMFullscreenTransition) {
-    // We shouldn't use native fullscreen for DOM fullscreen.
+  if (!aUseSystemTransition) {
+    // If we do not want the system fullscreen transition,
+    // don't use the native fullscreen.
     return false;
   }
-  // If we are using native fullscreen, we should have returned earlier,
-  // which means if we reach here for exiting fullscreen, we must be
-  // exiting from DOM fullscreen, not native fullscreen.
+  // If we are using native fullscreen, we should have returned earlier.
   return aFullScreen;
 }
 
-NS_METHOD nsCocoaWindow::MakeFullScreen(bool aFullScreen, nsIScreen* aTargetScreen)
+NS_IMETHODIMP
+nsCocoaWindow::MakeFullScreen(bool aFullScreen, nsIScreen* aTargetScreen)
+{
+  return DoMakeFullScreen(aFullScreen, false);
+}
+
+NS_IMETHODIMP
+nsCocoaWindow::MakeFullScreenWithNativeTransition(bool aFullScreen,
+                                                  nsIScreen* aTargetScreen)
+{
+  return DoMakeFullScreen(aFullScreen, true);
+}
+
+nsresult
+nsCocoaWindow::DoMakeFullScreen(bool aFullScreen, bool aUseSystemTransition)
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
 
@@ -1322,7 +1331,7 @@ static unsigned int WindowMaskForBorderStyle(nsBorderStyle aBorderStyle)
 
   mInFullScreenTransition = true;
 
-  if (ShouldToggleNativeFullscreen(aFullScreen)) {
+  if (ShouldToggleNativeFullscreen(aFullScreen, aUseSystemTransition)) {
     // If we're using native fullscreen mode and our native window is invisible,
     // our attempt to go into fullscreen mode will fail with an assertion in
     // system code, without [WindowDelegate windowDidFailToEnterFullScreen:]
@@ -1350,11 +1359,6 @@ static unsigned int WindowMaskForBorderStyle(nsBorderStyle aBorderStyle)
     EnteredFullScreen(aFullScreen, /* aNativeMode */ false);
   }
 
-  if (mInDOMFullscreenTransition) {
-    // Clear the flag about DOM fullscreen.
-    mInDOMFullscreenTransition = false;
-  }
-
   return NS_OK;
 
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
diff --git a/widget/nsBaseWidget.h b/widget/nsBaseWidget.h
index dfb4a184b703..12838e0b043b 100644
--- a/widget/nsBaseWidget.h
+++ b/widget/nsBaseWidget.h
@@ -143,8 +143,8 @@ class nsBaseWidget : public nsIWidget, public nsSupportsWeakReference
   virtual void            SetShowsFullScreenButton(bool aShow) override {}
   virtual void            SetWindowAnimationType(WindowAnimationType aType) override {}
   NS_IMETHOD              HideWindowChrome(bool aShouldHide) override;
-  virtual void            PrepareForDOMFullscreenTransition() override {}
   NS_IMETHOD              MakeFullScreen(bool aFullScreen, nsIScreen* aScreen = nullptr) override;
+
   virtual LayerManager*   GetLayerManager(PLayerTransactionChild* aShadowManager = nullptr,
                                           LayersBackend aBackendHint = mozilla::layers::LayersBackend::LAYERS_NONE,
                                           LayerManagerPersistence aPersistence = LAYER_MANAGER_CURRENT,
diff --git a/widget/nsIWidget.h b/widget/nsIWidget.h
index cb3aa50d7fba..7eaa4889a8d1 100644
--- a/widget/nsIWidget.h
+++ b/widget/nsIWidget.h
@@ -119,8 +119,8 @@ typedef void* nsNativeWidget;
 #define NS_NATIVE_PLUGIN_ID            105
 
 #define NS_IWIDGET_IID \
-{ 0x53376F57, 0xF081, 0x4949, \
-  { 0xB5, 0x5E, 0x87, 0xEF, 0x6A, 0xE9, 0xE3, 0x5A } };
+{ 0xb81e1264, 0x9f79, 0x4962, \
+  { 0x8d, 0x9a, 0x64, 0xdd, 0x21, 0x5d, 0x6a, 0x01 } }
 
 /*
  * Window shadow styles
@@ -1696,19 +1696,6 @@ class nsIWidget : public nsISupports {
      */
     NS_IMETHOD HideWindowChrome(bool aShouldHide) = 0;
 
-    /**
-     * Ask the widget to start the transition for entering or exiting
-     * DOM Fullscreen.
-     *
-     * XXX This method is currently not actually implemented by any
-     * widget. The only function of this method is to notify cocoa
-     * window that it should not use the native fullscreen mode. This
-     * method is reserved for bug 1160014 where a transition will be
-     * added for DOM fullscreen. Hence, this function is likely to
-     * be further changed then.
-     */
-    virtual void PrepareForDOMFullscreenTransition() = 0;
-
     /**
      * Put the toplevel window into or out of fullscreen mode.
      * If aTargetScreen is given, attempt to go fullscreen on that screen,
@@ -1718,6 +1705,18 @@ class nsIWidget : public nsISupports {
      */
     NS_IMETHOD MakeFullScreen(bool aFullScreen, nsIScreen* aTargetScreen = nullptr) = 0;
 
+    /**
+     * Same as MakeFullScreen, except that, on systems which natively
+     * support fullscreen transition, calling this method explicitly
+     * requests that behavior.
+     * It is currently only supported on OS X 10.7+.
+     */
+    NS_IMETHOD MakeFullScreenWithNativeTransition(
+      bool aFullScreen, nsIScreen* aTargetScreen = nullptr)
+    {
+      return MakeFullScreen(aFullScreen, aTargetScreen);
+    }
+
     /**
      * Invalidate a specified rect for a widget so that it will be repainted
      * later.