Use const ref for LocalFrame::LocalFrameRoot and FrameTree::Top

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 1908 matching lines @@
   // Don't check for paint invalidation here; we need to wait until the layer
   // has been updated by subclasses before we know if we have to invalidate
   // paints (in setStyle()).
 
   if (old_style && !AreCursorsEqual(old_style, Style())) {
     if (LocalFrame* frame = this->GetFrame()) {
       // Cursor update scheduling is done by the local root, which is the main
       // frame if there are no RemoteFrame ancestors in the frame tree. Use of
       // localFrameRoot() is discouraged but will change when cursor update
       // scheduling is moved from EventHandler to PageEventHandler.
-      frame->LocalFrameRoot()->GetEventHandler().ScheduleCursorUpdate();
+      frame->LocalFrameRoot().GetEventHandler().ScheduleCursorUpdate();
     }
   }
 
   if (diff.NeedsFullPaintInvalidation() && old_style) {
     if (ResolveColor(*old_style, CSSPropertyBackgroundColor) !=
             ResolveColor(CSSPropertyBackgroundColor) ||
         old_style->BackgroundLayers() != StyleRef().BackgroundLayers())
       SetBackgroundChangedSinceLastPaintInvalidation();
   }
 
@@ skipping 1695 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->Parent())
       root = root->Parent();
     root->ShowLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif