Revert "Remove the HTMLVideoElement-specific prefixed fullscreen API"

Source/core/html/HTMLVideoElement.cpp

Index: Source/core/html/HTMLVideoElement.cpp
diff --git a/Source/core/html/HTMLVideoElement.cpp b/Source/core/html/HTMLVideoElement.cpp
index d0b8b8d57e1bbd379de5dc66273ee639758867a4..5dacbacc390dee9573b52b3935ee2152861bd16b 100644
--- a/Source/core/html/HTMLVideoElement.cpp
+++ b/Source/core/html/HTMLVideoElement.cpp
@@ -120,6 +120,17 @@ void HTMLVideoElement::parseAttribute(const QualifiedName& name, const AtomicStr
         HTMLMediaElement::parseAttribute(name, value);
 }
 
+bool HTMLVideoElement::supportsFullscreen() const
+{
+    if (!document().page())
+        return false;
+
+    if (!player())
+        return false;
+
+    return true;
+}
+
 unsigned HTMLVideoElement::videoWidth() const
 {
     if (!player())
@@ -196,6 +207,41 @@ bool HTMLVideoElement::hasAvailableVideoFrame() const
     return player()->hasVideo() && player()->readyState() >= MediaPlayer::HaveCurrentData;
 }
 
+void HTMLVideoElement::webkitEnterFullscreen(ExceptionState& exceptionState)
+{
+    if (isFullscreen())
+        return;
+
+    // Generate an exception if this isn't called in response to a user gesture, or if the
+    // element does not support fullscreen.
+    if (userGestureRequiredForFullscreen() && !UserGestureIndicator::processingUserGesture()) {
+        exceptionState.throwDOMException(InvalidStateError, "This element may only enter fullscreen mode in response to a user gesture ('click', for example).");
+        return;
+    }
+    if (!supportsFullscreen()) {
+        exceptionState.throwDOMException(InvalidStateError, "This element does not support fullscreen mode.");
+        return;
+    }
+
+    enterFullscreen();
+}
+
+void HTMLVideoElement::webkitExitFullscreen()
+{
+    if (isFullscreen())
+        exitFullscreen();
+}
+
+bool HTMLVideoElement::webkitSupportsFullscreen()
+{
+    return supportsFullscreen();
+}
+
+bool HTMLVideoElement::webkitDisplayingFullscreen()
+{
+    return isFullscreen();
+}
+
 void HTMLVideoElement::didMoveToNewDocument(Document& oldDocument)
 {
     if (m_imageLoader)