Implement the unprefixed the Fullscreen API

Source/core/dom/FullscreenElementStack.h

Index: Source/core/dom/FullscreenElementStack.h
diff --git a/Source/core/dom/FullscreenElementStack.h b/Source/core/dom/FullscreenElementStack.h
index 9f24ee07d638601a50b8c808471573959ba92733..41dd652cefb6f5996cfd9ae3c5031e131d77418d 100644
--- a/Source/core/dom/FullscreenElementStack.h
+++ b/Source/core/dom/FullscreenElementStack.h
@@ -59,6 +59,7 @@ public:
     static bool isActiveFullScreenElement(const Element&);
 
     enum RequestType {
+        UnprefixedRequest, // Element.requestFullscreen()
         PrefixedRequest, // Element.webkitRequestFullscreen()
         PrefixedMozillaRequest, // Element.webkitRequestFullScreen()
         PrefixedMozillaAllowKeyboardInputRequest, // Element.webkitRequestFullScreen(Element.ALLOW_KEYBOARD_INPUT)
@@ -70,7 +71,7 @@ public:
     void exitFullscreen();
 
     static bool fullscreenEnabled(Document&);
-    Element* fullscreenElement() const { return !m_fullScreenElementStack.isEmpty() ? m_fullScreenElementStack.last().get() : 0; }
+    Element* fullscreenElement() const { return !m_fullScreenElementStack.isEmpty() ? m_fullScreenElementStack.last().first.get() : 0; }
 
     void willEnterFullScreenForElement(Element*);
     void didEnterFullScreenForElement(Element*);
@@ -104,17 +105,17 @@ private:
 
     void clearFullscreenElementStack();
     void popFullscreenElementStack();
-    void pushFullscreenElementStack(Element&);
+    void pushFullscreenElementStack(Element&, RequestType);
 
-    void enqueueChangeEvent(Document&);
-    void enqueueErrorEvent(Element&);
+    void enqueueChangeEvent(Document&, RequestType);
+    void enqueueErrorEvent(Element&, RequestType);
     void eventQueueTimerFired(Timer<FullscreenElementStack>*);
 
     void fullScreenElementRemoved();
 
     bool m_areKeysEnabledInFullScreen;
     RefPtrWillBeMember<Element> m_fullScreenElement;
-    WillBeHeapVector<RefPtrWillBeMember<Element> > m_fullScreenElementStack;
+    WillBeHeapVector<std::pair<RefPtrWillBeMember<Element>, RequestType> > m_fullScreenElementStack;
     RawPtrWillBeMember<RenderFullScreen> m_fullScreenRenderer;
     Timer<FullscreenElementStack> m_eventQueueTimer;
     WillBeHeapDeque<RefPtrWillBeMember<Event> > m_eventQueue;