Have Frame::animation() return a reference

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 2010 matching lines @@
 
     m_layoutTimer.stop();
     m_delayedLayout = false;
 }
 
 void FrameView::serviceScriptedAnimations(double monotonicAnimationStartTime)
 {
     for (RefPtr<Frame> frame = m_frame; frame; frame = frame->tree()->traverseNext()) {
         frame->view()->serviceScrollAnimations();
         if (!RuntimeEnabledFeatures::webAnimationsCSSEnabled())
-            frame->animation()->serviceAnimations();
+            frame->animation().serviceAnimations();
         if (RuntimeEnabledFeatures::webAnimationsEnabled())
             frame->document()->timeline()->serviceAnimations(monotonicAnimationStartTime);
     }
 
     Vector<RefPtr<Document> > documents;
     for (Frame* frame = m_frame.get(); frame; frame = frame->tree()->traverseNext())
         documents.append(frame->document());
 
     for (size_t i = 0; i < documents.size(); ++i)
         documents[i]->serviceScriptedAnimations(monotonicAnimationStartTime);
@@ skipping 1410 matching lines @@
 void FrameView::setLayoutSizeInternal(const IntSize& size)
 {
     if (m_layoutSize == size)
         return;
 
     m_layoutSize = size;
     contentsResized();
 }
 
 } // namespace WebCore