Pass implementation object to supplemental classes by reference

Source/modules/screen_orientation/ScreenOrientation.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/screen_orientation/ScreenOrientation.h"
 
 #include "core/frame/DOMWindow.h"
 #include "core/frame/Frame.h"
 #include "core/frame/Screen.h"
 
 namespace WebCore {
 
-ScreenOrientation::ScreenOrientation(Screen* screen)
-    : DOMWindowProperty(screen->frame())
+ScreenOrientation::ScreenOrientation(Screen& screen)
+    : DOMWindowProperty(screen.frame())
 {
 }
 
 const char* ScreenOrientation::supplementName()
 {
     return "ScreenOrientation";
 }
 
-ScreenOrientation* ScreenOrientation::from(Screen* screen)
+ScreenOrientation& ScreenOrientation::from(Screen& screen)
 {
     ScreenOrientation* supplement = static_cast<ScreenOrientation*>(Supplement<Screen>::from(screen, supplementName()));
     if (!supplement) {
-        ASSERT(screen);
         supplement = new ScreenOrientation(screen);
         provideTo(screen, supplementName(), adoptPtr(supplement));
     }
-    return supplement;
+    return *supplement;
 }
 
 ScreenOrientation::~ScreenOrientation()
 {
 }
 
 Screen* ScreenOrientation::screen() const
 {
     Frame* frame = this->frame();
     ASSERT(frame);
     DOMWindow* window = frame->domWindow();
     ASSERT(window);
     return window->screen();
 }
 
-const AtomicString& ScreenOrientation::orientation(Screen* screen)
+const AtomicString& ScreenOrientation::orientation(Screen& screen)
 {
     // FIXME: Implement.
     DEFINE_STATIC_LOCAL(const AtomicString, portraitPrimary, ("portrait-primary", AtomicString::ConstructFromLiteral));
     return portraitPrimary;
 }
 
-bool ScreenOrientation::lockOrientation(Screen* screen, const Vector<String>& orientations)
+bool ScreenOrientation::lockOrientation(Screen& screen, const Vector<String>& orientations)
 {
     // FIXME: Implement.
     return false;
 }
 
-bool ScreenOrientation::lockOrientation(Screen* screen, const AtomicString& orientation)
+bool ScreenOrientation::lockOrientation(Screen& screen, const AtomicString& orientation)
 {
     // FIXME: Implement.
     return false;
 }
 
-void ScreenOrientation::unlockOrientation(Screen* screen)
+void ScreenOrientation::unlockOrientation(Screen& screen)
 {
     // FIXME: Implement.
 }
 
 } // namespace WebCore