Webkit setting for embedders that do not support fullscreen.

Source/core/loader/EmptyClients.h

Index: Source/core/loader/EmptyClients.h
diff --git a/Source/core/loader/EmptyClients.h b/Source/core/loader/EmptyClients.h
index 8b8d49b641eec35fa694616d56395f027e1bdf5c..99b11b125031a710b583cc61dbbb40e48ee1ef01 100644
--- a/Source/core/loader/EmptyClients.h
+++ b/Source/core/loader/EmptyClients.h
@@ -153,6 +153,8 @@ public:
 
     virtual void attachRootGraphicsLayer(GraphicsLayer*) OVERRIDE { }
 
+    virtual bool fullscreenEnabled(Element*) OVERRIDE { return false; }
+
     virtual void needTouchEvents(bool) OVERRIDE { }
     virtual void setTouchAction(TouchAction touchAction) OVERRIDE { };