Add initial Blink-side support for the Screen Orientation API

Source/core/frame/Screen.cpp

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 102 matching lines @@
 unsigned Screen::availWidth() const
 {
     if (!m_frame)
         return 0;
     FrameHost* host = m_frame->host();
     if (host && host->settings().reportScreenSizeInPhysicalPixelsQuirk())
         return lroundf(screenAvailableRect(m_frame->view()).width() * host->deviceScaleFactor());
     return static_cast<unsigned>(screenAvailableRect(m_frame->view()).width());
 }
 
+const AtomicString& Screen::interfaceName() const
+{
+    return EventTargetNames::Screen;
+}
+
+ExecutionContext* Screen::executionContext() const
+{
+    if (!m_frame)
+        return 0;
+    return m_frame->document();
+}
+
 } // namespace WebCore