Assert that CFX_ strings are pointer-size.

core/fxcrt/fx_basic_bstring.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>
 
 #include <algorithm>
 #include <cctype>
@@ skipping 57 matching lines @@
         return haystack;
       }
     }
     haystack++;
   }
   return nullptr;
 }
 
 }  // namespace
 
+static_assert(sizeof(CFX_ByteString) <= sizeof(FX_CHAR*),
+              "Strings must not require more space than pointers");
+
 CFX_ByteString::CFX_ByteString(const FX_CHAR* pStr, FX_STRSIZE nLen) {
   if (nLen < 0)
     nLen = pStr ? FXSYS_strlen(pStr) : 0;
 
   if (nLen)
     m_pData.Reset(StringData::Create(pStr, nLen));
 }
 
 CFX_ByteString::CFX_ByteString(const uint8_t* pStr, FX_STRSIZE nLen) {
   if (nLen > 0) {
@@ skipping 899 matching lines @@
     fraction %= scale;
     scale /= 10;
   }
   return buf_size;
 }
 CFX_ByteString CFX_ByteString::FormatFloat(FX_FLOAT d, int precision) {
   FX_CHAR buf[32];
   FX_STRSIZE len = FX_ftoa(d, buf);
   return CFX_ByteString(buf, len);
 }