Fixes for re-enabling more MSVC level 4 warnings: Source/core/ edition

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 20 matching lines @@
 #include "wtf/Vector.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/StringBuilder.h"
 
 using std::swap;
 
 namespace WebCore {
 
 namespace {
 
-const unsigned invalidChildCount = ~0;
+const unsigned invalidChildCount = ~0U;
 
 } // namespace
 
 FrameTree::FrameTree(Frame* thisFrame)
     : m_thisFrame(thisFrame)
     , m_scopedChildCount(invalidChildCount)
 {
 }
 
 FrameTree::~FrameTree()
@@ skipping 362 matching lines @@
 {
     if (!frame) {
         printf("Null input frame\n");
         return;
     }
 
     printFrames(frame->tree().top(), frame, 0);
 }
 
 #endif