Revert "Remove FX_Alloc() null checks now that it can't return NULL."

core/src/fxcrt/xml_int.h

 // 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
 
 #ifndef _FXCRT_XML_INT_
 #define _FXCRT_XML_INT_
 class CXML_DataBufAcc : public IFX_BufferRead
 {
@@ skipping 89 matching lines @@
             m_nStart = 0;
         }
         FX_FILESIZE nLength = m_pFileRead->GetSize();
         m_nStart += (FX_FILESIZE)m_dwSize;
         if (m_nStart >= nLength) {
             return FALSE;
         }
         m_dwSize = (size_t)FX_MIN(FX_XMLDATASTREAM_BufferSize, nLength - m_nStart);
         if (!m_pBuffer) {
             m_pBuffer = FX_Alloc(FX_BYTE, m_dwSize);
+            if (!m_pBuffer) {
+                return FALSE;
+            }
         }
         return m_pFileRead->ReadBlock(m_pBuffer, m_nStart, m_dwSize);
     }
     virtual FX_LPCBYTE          GetBlockBuffer()
     {
         return (FX_LPCBYTE)m_pBuffer;
     }
     virtual size_t                      GetBlockSize()
     {
         return m_dwSize;
@@ skipping 32 matching lines @@
     void                        GetAttrValue(CFX_WideString &value);
     FX_DWORD            GetCharRef();
     void                        GetTagName(CFX_ByteString &space, CFX_ByteString &name, FX_BOOL &bEndTag, FX_BOOL bStartTag = FALSE);
     void                        SkipLiterals(FX_BSTR str);
     CXML_Element*       ParseElement(CXML_Element* pParent, FX_BOOL bStartTag = FALSE);
     void                        InsertContentSegment(FX_BOOL bCDATA, FX_WSTR content, CXML_Element* pElement);
     void                        InsertCDATASegment(CFX_UTF8Decoder& decoder, CXML_Element* pElement);
 };
 void FX_XML_SplitQualifiedName(FX_BSTR bsFullName, CFX_ByteStringC &bsSpace, CFX_ByteStringC &bsName);
 #endif