Have Frame::animation() return a reference

Source/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 936 matching lines @@
     virtual int nextOffset(int current) const;
 
     virtual void imageChanged(ImageResource*, const IntRect* = 0);
     virtual void imageChanged(WrappedImagePtr, const IntRect* = 0) { }
     virtual bool willRenderImage(ImageResource*);
 
     void selectionStartEnd(int& spos, int& epos) const;
 
     void remove() { if (parent()) parent()->removeChild(this); }
 
-    AnimationController* animation() const;
+    AnimationController& animation() const;
 
     bool isInert() const;
     bool visibleToHitTestRequest(const HitTestRequest& request) const { return style()->visibility() == VISIBLE && (request.ignorePointerEventsNone() || style()->pointerEvents() != PE_NONE) && !isInert(); }
     bool visibleToHitTesting() const { return style()->visibility() == VISIBLE && style()->pointerEvents() != PE_NONE && !isInert(); }
 
     // Map points and quads through elements, potentially via 3d transforms. You should never need to call these directly; use
     // localToAbsolute/absoluteToLocal methods instead.
     virtual void mapLocalToContainer(const RenderLayerModelObject* repaintContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip, bool* wasFixed = 0) const;
     virtual void mapAbsoluteToLocalPoint(MapCoordinatesFlags, TransformState&) const;
 
@@ skipping 422 matching lines @@
 void showTree(const WebCore::RenderObject*);
 void showLineTree(const WebCore::RenderObject*);
 void showRenderTree(const WebCore::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const WebCore::RenderObject* object1, const WebCore::RenderObject* object2);
 
 #endif
 
 #endif // RenderObject_h