Implement the unprefixed the Fullscreen API

Source/core/dom/DocumentFullscreen.h

Index: Source/core/dom/DocumentFullscreen.h
diff --git a/Source/core/dom/DocumentFullscreen.h b/Source/core/dom/DocumentFullscreen.h
index 2096c2f379950236e720f7eb13803894b6a5c3a3..341cfac23ea41ac08cf629df40ded0a70dbdfbd7 100644
--- a/Source/core/dom/DocumentFullscreen.h
+++ b/Source/core/dom/DocumentFullscreen.h
@@ -35,14 +35,18 @@ class Element;
 
 class DocumentFullscreen {
 public:
+    static bool fullscreenEnabled(Document&);
+    static Element* fullscreenElement(Document&);
+    static void exitFullscreen(Document&);
+
+    DEFINE_STATIC_ATTRIBUTE_EVENT_LISTENER(fullscreenchange);
+    DEFINE_STATIC_ATTRIBUTE_EVENT_LISTENER(fullscreenerror);
+
+    // Mozilla version
     static bool webkitIsFullScreen(Document&);
     static bool webkitFullScreenKeyboardInputAllowed(Document&);
     static Element* webkitCurrentFullScreenElement(Document&);
 
-    static bool webkitFullscreenEnabled(Document&);
-    static Element* webkitFullscreenElement(Document&);
-    static void webkitExitFullscreen(Document&);
-
     DEFINE_STATIC_ATTRIBUTE_EVENT_LISTENER(webkitfullscreenchange);
     DEFINE_STATIC_ATTRIBUTE_EVENT_LISTENER(webkitfullscreenerror);
 };