Revert of wtf/CheckedArithmetic.h delegates to base/numerics/safe_math.h.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2013 Apple Inc. All rights reserved.
  *
  * 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.
  *
@@ skipping 13 matching lines @@
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/MutationObserverInterestGroup.h"
 #include "core/dom/MutationRecord.h"
 #include "core/dom/ProcessingInstruction.h"
 #include "core/dom/Text.h"
 #include "core/editing/FrameSelection.h"
 #include "core/events/MutationEvent.h"
 #include "core/inspector/InspectorInstrumentation.h"
-#include "wtf/CheckedNumeric.h"
+#include "wtf/CheckedArithmetic.h"
 
 namespace blink {
 
 void CharacterData::atomize()
 {
     m_data = AtomicString(m_data);
 }
 
 void CharacterData::setData(const String& data)
 {
@@ skipping 50 matching lines @@
     document().didInsertText(this, offset, data.length());
 }
 
 static bool validateOffsetCount(unsigned offset, unsigned count, unsigned length, unsigned& realCount, ExceptionState& exceptionState)
 {
     if (offset > length) {
         exceptionState.throwDOMException(IndexSizeError, "The offset " + String::number(offset) + " is greater than the node's length (" + String::number(length) + ").");
         return false;
     }
 
-    CheckedNumeric<unsigned> offsetCount = offset;
+    Checked<unsigned, RecordOverflow> offsetCount = offset;
     offsetCount += count;
 
-    if (!offsetCount.IsValid() || offset + count > length)
+    if (offsetCount.hasOverflowed() || offset + count > length)
         realCount = length - offset;
     else
         realCount = count;
 
     return true;
 }
 
 void CharacterData::deleteData(unsigned offset, unsigned count, ExceptionState& exceptionState, RecalcStyleBehavior recalcStyleBehavior)
 {
     unsigned realCount = 0;
@@ skipping 81 matching lines @@
     }
     InspectorInstrumentation::characterDataModified(this);
 }
 
 int CharacterData::maxCharacterOffset() const
 {
     return static_cast<int>(length());
 }
 
 } // namespace blink