core/platform: Include wtf files using "wtf/foo.h" form.

Source/core/platform/text/mac/StringMac.mm

 /**
  * 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #include "config.h"
-#include <wtf/text/WTFString.h>
+#include "wtf/text/WTFString.h"
 
 #include <CoreFoundation/CFString.h>
 
 namespace WTF {
 
 String::String(NSString* str)
 {
     if (!str)
         return;
 
     CFIndex size = CFStringGetLength(reinterpret_cast<CFStringRef>(str));
     if (size == 0)
         m_impl = StringImpl::empty();
     else {
         Vector<LChar, 1024> lcharBuffer(size);
         CFIndex usedBufLen;
         CFIndex convertedsize = CFStringGetBytes(reinterpret_cast<CFStringRef>(str), CFRangeMake(0, size), kCFStringEncodingISOLatin1, 0, false, lcharBuffer.data(), size, &usedBufLen);
         if ((convertedsize == size) && (usedBufLen == size)) {
             m_impl = StringImpl::create(lcharBuffer.data(), size);
             return;
         }
 
         Vector<UChar, 1024> ucharBuffer(size);
         CFStringGetCharacters(reinterpret_cast<CFStringRef>(str), CFRangeMake(0, size), ucharBuffer.data());
         m_impl = StringImpl::create(ucharBuffer.data(), size);
     }
 }
 
 }