Support subtitles for native fullscreen video

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 1c0ca09910247206a7fc9f91065c1d604bb83024..7591bd2178673a2a49004047efc4bf0f3eafe67b 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -1350,6 +1350,11 @@ void Element::attach(const AttachContext& context)
     // lazyAttach in the future that problem should go away.
     if (document()->inStyleRecalc())
         InspectorInstrumentation::didRecalculateStyleForElement(this);
+
+    if (FullscreenElementStack::isActiveFullScreenElement(this)) {
+        if (FrameView* view = document()->view())
+            view->setCurrentFullscreenRenderer(renderer());
+    }
 }
 
 void Element::unregisterNamedFlowContentNode()
@@ -1360,6 +1365,11 @@ void Element::unregisterNamedFlowContentNode()
 
 void Element::detach(const AttachContext& context)
 {
+    if (FullscreenElementStack::isActiveFullScreenElement(this)) {
+        if (FrameView* view = document()->view())
+            view->setCurrentFullscreenRenderer(0);
+    }
+
     WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;
     unregisterNamedFlowContentNode();
     cancelFocusAppearanceUpdate();
@@ -3651,4 +3661,20 @@ Attribute* UniqueElementData::attributeItem(unsigned index)
     return &m_attributeVector.at(index);
 }
 
+void Element::didBecomeFullscreenElement()
+{
+    FrameView* view = document()->view();
+    if (!view)
+        return;
+    view->setCurrentFullscreenRenderer(renderer());
+}
+
+void Element::willStopBeingFullscreenElement()
+{
+    FrameView* view = document()->view();
+    if (!view)
+        return;
+    view->setCurrentFullscreenRenderer(0);
+}
+
 } // namespace WebCore