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

third_party/WebKit/Source/web/WebPluginContainerImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2014 Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 711 matching lines @@
     event->SetDefaultHandled();
 
   // A windowless plugin can change the cursor in response to a mouse move
   // event.  We need to reflect the changed cursor in the frame view as the
   // mouse is moved in the boundaries of the windowless plugin.
   Page* page = parent_view->GetFrame().GetPage();
   if (!page)
     return;
   ToChromeClientImpl(page->GetChromeClient())
       .SetCursorForPlugin(cursor_info,
-                          parent_view->GetFrame().LocalFrameRoot());
+                          &parent_view->GetFrame().LocalFrameRoot());
 }
 
 void WebPluginContainerImpl::HandleDragEvent(MouseEvent* event) {
   DCHECK(event->IsDragEvent());
 
   WebDragStatus drag_status = kWebDragStatusUnknown;
   if (event->type() == EventTypeNames::dragenter)
     drag_status = kWebDragStatusEnter;
   else if (event->type() == EventTypeNames::dragleave)
     drag_status = kWebDragStatusLeave;
@@ skipping 260 matching lines @@
     ComputeClipRectsForPlugin(element_, window_rect, clip_rect,
                               unobscured_rect);
   }
   GetPluginOcclusions(element_, parent_, frame_rect_, cut_out_rects);
   // Convert to the plugin position.
   for (size_t i = 0; i < cut_out_rects.size(); i++)
     cut_out_rects[i].Move(-frame_rect_.X(), -frame_rect_.Y());
 }
 
 }  // namespace blink