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

third_party/WebKit/Source/core/page/FrameTree.cpp

 /*
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 57 matching lines @@
   name_ = name;
 }
 
 DISABLE_CFI_PERF
 Frame* FrameTree::Parent() const {
   if (!this_frame_->Client())
     return nullptr;
   return this_frame_->Client()->Parent();
 }
 
-Frame* FrameTree::Top() const {
+Frame& FrameTree::Top() const {
   // FIXME: top() should never return null, so here are some hacks to deal
   // with EmptyLocalFrameClient and cases where the frame is detached
   // already...
   if (!this_frame_->Client())
-    return this_frame_;
+    return *this_frame_;
   Frame* candidate = this_frame_->Client()->Top();
-  return candidate ? candidate : this_frame_.Get();
+  return candidate ? *candidate : *this_frame_;
 }
 
 Frame* FrameTree::NextSibling() const {
   if (!this_frame_->Client())
     return nullptr;
   return this_frame_->Client()->NextSibling();
 }
 
 Frame* FrameTree::FirstChild() const {
   if (!this_frame_->Client())
@@ skipping 51 matching lines @@
     ++count;
   return count;
 }
 
 Frame* FrameTree::Find(const AtomicString& name) const {
   if (EqualIgnoringASCIICase(name, "_self") ||
       EqualIgnoringASCIICase(name, "_current") || name.IsEmpty())
     return this_frame_;
 
   if (EqualIgnoringASCIICase(name, "_top"))
-    return Top();
+    return &Top();
 
   if (EqualIgnoringASCIICase(name, "_parent"))
     return Parent() ? Parent() : this_frame_.Get();
 
   // Since "_blank" should never be any frame's name, the following just amounts
   // to an optimization.
   if (EqualIgnoringASCIICase(name, "_blank"))
     return nullptr;
 
   // Search subtree starting with this frame first.
@@ skipping 128 matching lines @@
 void showFrameTree(const blink::Frame* frame) {
   if (!frame) {
     printf("Null input frame\n");
     return;
   }
 
   printFrames(frame->Tree().Top(), frame, 0);
 }
 
 #endif