Remove failing DCHECKs in Blob code.

webkit/common/blob/blob_data.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 "webkit/common/blob/blob_data.h"
 
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 
 namespace webkit_blob {
 
 BlobData::BlobData() {}
 BlobData::BlobData(const std::string& uuid)
     : uuid_(uuid) {
 }
 
 BlobData::~BlobData() {}
 
 void BlobData::AppendData(const char* data, size_t length) {
   DCHECK(length > 0);
   items_.push_back(Item());
   items_.back().SetToBytes(data, length);
 }
 
 void BlobData::AppendFile(const base::FilePath& file_path,
                           uint64 offset, uint64 length,
                           const base::Time& expected_modification_time) {
-  DCHECK(length > 0);
   items_.push_back(Item());
   items_.back().SetToFilePathRange(file_path, offset, length,
                                    expected_modification_time);
 }
 
 void BlobData::AppendBlob(const std::string& uuid,
                           uint64 offset, uint64 length) {
   DCHECK_GT(length, 0ul);

[cmumford, 2014/07/31 18:44:43]

If's OK to support empty files (which makes sense) what about empty BLOB's?

[pwnall-personal, 2014/07/31 19:34:47]

I was not able to trigger this DCHECK... and I tried :/

new Blob([])
new Blob(["", "", ""])
new Blob(["", new Blob([]), ""])

I admit I haven't looked too much in the code, and I just tried wicked things.
Is there anything that you think would work?

If I can't trigger the DCHECK, I don't think I should remove it.

   items_.push_back(Item());
   items_.back().SetToBlobRange(uuid, offset, length);
 }
 
 void BlobData::AppendFileSystemFile(
     const GURL& url, uint64 offset,
     uint64 length,
     const base::Time& expected_modification_time) {
-  DCHECK(length > 0);
   items_.push_back(Item());
   items_.back().SetToFileSystemUrlRange(url, offset, length,
                                         expected_modification_time);
 }
 
 int64 BlobData::GetMemoryUsage() const {
   int64 memory = 0;
   for (std::vector<Item>::const_iterator iter = items_.begin();
        iter != items_.end(); ++iter) {
     if (iter->type() == Item::TYPE_BYTES)
       memory += iter->length();
   }
   return memory;
 }
 
 }  // namespace webkit_blob