Remove DCHECK which causes crash in PDFs with email attachments.

pdf/pdfium/pdfium_engine.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 
 #include "base/json/json_writer.h"
 #include "base/logging.h"
@@ skipping 3597 matching lines @@
 
 void PDFiumEngine::Form_Mail(IPDF_JSPLATFORM* param,
                              void* mail_data,
                              int length,
                              FPDF_BOOL ui,
                              FPDF_WIDESTRING to,
                              FPDF_WIDESTRING subject,
                              FPDF_WIDESTRING cc,
                              FPDF_WIDESTRING bcc,
                              FPDF_WIDESTRING message) {
-  DCHECK(length == 0);  // Don't handle attachments; no way with mailto.
+  // Note: |mail_data| and |length| are ignored. We don't handle attachments;
+  // there is no way with mailto.
   std::string to_str =
       base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(to));
   std::string cc_str =
       base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(cc));
   std::string bcc_str =
       base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(bcc));
   std::string subject_str =
       base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(subject));
   std::string message_str =
       base::UTF16ToUTF8(reinterpret_cast<const base::char16*>(message));
@@ skipping 286 matching lines @@
     double* height) {
   FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, NULL);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf