wstring allocations waste up to 7 wasted bytes.

core/src/fxcrt/fx_basic_wstring.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include <stddef.h>  // For offsetof().
 
 #include "../../include/fxcrt/fx_basic.h"
 #include "../../../third_party/base/numerics/safe_math.h"
@@ skipping 14 matching lines @@
 
   // Now round to an 8-byte boundary. We'd expect that this is the minimum
   // granularity of any of the underlying allocators, so there may be cases
   // where we can save a re-alloc when adding a few characters to a string
   // by using this otherwise wasted space.
   iSize += 7;
   int totalSize = iSize.ValueOrDie() & ~7;
   int usableLen = (totalSize - overhead) / sizeof(FX_WCHAR);
   FXSYS_assert(usableLen >= nLen);
 
-  void* pData = FX_Alloc(uint8_t, iSize.ValueOrDie());
+  void* pData = FX_Alloc(uint8_t, totalSize);
   return new (pData) StringData(nLen, usableLen);
 }
 CFX_WideString::~CFX_WideString() {
   if (m_pData) {
     m_pData->Release();
   }
 }
 CFX_WideString::CFX_WideString(const CFX_WideString& stringSrc) {
   if (stringSrc.m_pData == NULL) {
     m_pData = NULL;
@@ skipping 1011 matching lines @@
       return (CFX_CharMap*)&g_DefaultJISMapper;
     case 936:
       return (CFX_CharMap*)&g_DefaultGBKMapper;
     case 949:
       return (CFX_CharMap*)&g_DefaultUHCMapper;
     case 950:
       return (CFX_CharMap*)&g_DefaultBig5Mapper;
   }
   return NULL;
 }