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

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 4894 matching lines @@
   // If this is an imported document, grab its master document's first-party:
   if (ImportsController() && ImportsController()->Master() &&
       ImportsController()->Master() != this)
     return ImportsController()->Master()->FirstPartyForCookies();
 
   if (!GetFrame())
     return SecurityOrigin::UrlWithUniqueSecurityOrigin();
 
   // TODO(mkwst): This doesn't correctly handle sandboxed documents; we want to
   // look at their URL, but we can't because we don't know what it is.
-  Frame* top = GetFrame()->Tree().Top();
+  Frame& top = GetFrame()->Tree().Top();
   KURL top_document_url =
-      top->IsLocalFrame()
-          ? ToLocalFrame(top)->GetDocument()->Url()
+      top.IsLocalFrame()
+          ? ToLocalFrame(top).GetDocument()->Url()
           : KURL(KURL(),
-                 top->GetSecurityContext()->GetSecurityOrigin()->ToString());
+                 top.GetSecurityContext()->GetSecurityOrigin()->ToString());
   if (SchemeRegistry::ShouldTreatURLSchemeAsFirstPartyWhenTopLevel(
           top_document_url.Protocol()))
     return top_document_url;
 
   // We're intentionally using the URL of each document rather than the
   // document's SecurityOrigin.  Sandboxing a document into a unique origin
   // shouldn't effect first-/third-party status for cookies and site data.
   const OriginAccessEntry& access_entry =
-      top->IsLocalFrame()
-          ? ToLocalFrame(top)->GetDocument()->AccessEntryFromURL()
+      top.IsLocalFrame()
+          ? ToLocalFrame(top).GetDocument()->AccessEntryFromURL()
           : OriginAccessEntry(top_document_url.Protocol(),
                               top_document_url.Host(),
                               OriginAccessEntry::kAllowRegisterableDomains);
   const Frame* current_frame = GetFrame();
   while (current_frame) {
     // Skip over srcdoc documents, as they are always same-origin with their
     // closest non-srcdoc parent.
     while (current_frame->IsLocalFrame() &&
            ToLocalFrame(current_frame)->GetDocument()->IsSrcdocDocument())
       current_frame = current_frame->Tree().Parent();
@@ skipping 1838 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (blink::Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->Url().GetString().Utf8().data());
 }
 #endif