Have Frame::tree() return a reference

Source/core/page/CreateWindow.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 48 matching lines @@
 
     // Sandboxed frames cannot open new auxiliary browsing contexts.
     if (openerFrame->document()->isSandboxed(SandboxPopups)) {
         // FIXME: This message should be moved off the console once a solution to https://bugs.webkit.org/show_bug.cgi?id=103274 exists.
         openerFrame->document()->addConsoleMessage(SecurityMessageSource, ErrorMessageLevel, "Blocked opening '" + request.resourceRequest().url().elidedString() + "' in a new window because the request was made in a sandboxed frame whose 'allow-popups' permission is not set.");
         return 0;
     }
 
     if (openerFrame->settings() && !openerFrame->settings()->supportsMultipleWindows()) {
         created = false;
-        return openerFrame->tree()->top();
+        return openerFrame->tree().top();
     }
 
     Page* oldPage = openerFrame->page();
     if (!oldPage)
         return 0;
 
     Page* page = oldPage->chrome().client().createWindow(openerFrame, request, features);
     if (!page)
         return 0;
 
     Frame* frame = page->mainFrame();
 
     frame->loader()->forceSandboxFlags(openerFrame->document()->sandboxFlags());
 
     if (request.frameName() != "_blank")
-        frame->tree()->setName(request.frameName());
+        frame->tree().setName(request.frameName());
 
     page->chrome().setWindowFeatures(features);
 
     // 'x' and 'y' specify the location of the window, while 'width' and 'height'
     // specify the size of the viewport. We can only resize the window, so adjust
     // for the difference between the window size and the viewport size.
 
     FloatRect windowRect = page->chrome().windowRect();
     FloatSize viewportSize = page->chrome().pageRect().size();
 
@@ skipping 54 matching lines @@
     if (created) {
         FrameLoadRequest request(activeWindow->document()->securityOrigin(), ResourceRequest(completedURL, referrer));
         newFrame->loader()->load(request);
     } else if (!urlString.isEmpty()) {
         newFrame->navigationScheduler()->scheduleLocationChange(activeWindow->document()->securityOrigin(), completedURL.string(), referrer, false);
     }
     return newFrame;
 }
 
 } // namespace WebCore