Implement the unprefixed the Fullscreen API

Source/core/dom/DocumentFullscreen.idl

Index: Source/core/dom/DocumentFullscreen.idl
diff --git a/Source/core/dom/DocumentFullscreen.idl b/Source/core/dom/DocumentFullscreen.idl
index 65c6f80058a6684bdf94e8a76f0160c72c41de42..bf71e8d8e6f90a12f7a9d0f5e53a6560613afffe 100644
--- a/Source/core/dom/DocumentFullscreen.idl
+++ b/Source/core/dom/DocumentFullscreen.idl
@@ -20,6 +20,14 @@
  */
 
 partial interface Document {
+    [RuntimeEnabled=FullscreenUnprefixed] readonly attribute boolean fullscreenEnabled;
+    [RuntimeEnabled=FullscreenUnprefixed] readonly attribute Element? fullscreenElement;
+
+    [RuntimeEnabled=FullscreenUnprefixed] void exitFullscreen();
+
+    [RuntimeEnabled=FullscreenUnprefixed] attribute EventHandler onfullscreenchange;
+    [RuntimeEnabled=FullscreenUnprefixed] attribute EventHandler onfullscreenerror;
+
     // Mozilla version
     [MeasureAs=PrefixedDocumentIsFullscreen] readonly attribute boolean webkitIsFullScreen;
     [MeasureAs=PrefixedDocumentFullScreenKeyboardInputAllowed] readonly attribute boolean webkitFullScreenKeyboardInputAllowed;
@@ -27,7 +35,7 @@ partial interface Document {
     [MeasureAs=PrefixedDocumentCancelFullScreen] void webkitCancelFullScreen();
 
     // W3C version
-    [MeasureAs=PrefixedDocumentFullscreenEnabled] readonly attribute boolean webkitFullscreenEnabled;
-    [MeasureAs=PrefixedDocumentFullscreenElement] readonly attribute Element webkitFullscreenElement;
-    [MeasureAs=PrefixedDocumentExitFullscreen] void webkitExitFullscreen();
+    [MeasureAs=PrefixedDocumentFullscreenEnabled, ImplementedAs=fullscreenEnabled] readonly attribute boolean webkitFullscreenEnabled;
+    [MeasureAs=PrefixedDocumentFullscreenElement, ImplementedAs=fullscreenElement] readonly attribute Element webkitFullscreenElement;
+    [MeasureAs=PrefixedDocumentExitFullscreen, ImplementedAs=exitFullscreen] void webkitExitFullscreen();
 };