Remove failing DCHECKs in Blob code.

webkit/browser/blob/blob_storage_context.cc

 // Copyright (c) 2013 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/browser/blob/blob_storage_context.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ skipping 125 matching lines @@
   // list of Data, File, and FileSystem items. Aggregated TYPE_BLOB items
   // are expanded into the primitive constituent types.
   // 1) The Data item is denoted by the raw data and length.
   // 2) The File item is denoted by the file path, the range and the expected
   //    modification time.
   // 3) The FileSystem File item is denoted by the FileSystem URL, the range
   //    and the expected modification time.
   // 4) The Blob items are expanded.
   // TODO(michaeln): Would be nice to avoid copying Data items when expanding.
 
-  DCHECK(item.length() > 0);

[michaeln, 2014/07/31 19:31:22]

These DCHECK's are here because higher level logic is expected to have filtered
out empty file and data elements before getting this far. Adding zero length
element adds nothing to the byte sequence the blob represents, so callers are
expected to weed them out so things like...

for(1 to a million) blob.add("");  // its not the real api but you get my point

... don't build big collections of nothingness.

   switch (item.type()) {
     case BlobData::Item::TYPE_BYTES:
       DCHECK(!item.offset());
       exceeded_memory = !AppendBytesItem(target_blob_data,
                                          item.bytes(),
                                          static_cast<int64>(item.length()));
       break;
     case BlobData::Item::TYPE_FILE:
       AppendFileItem(target_blob_data,
                      item.path(),
@@ skipping 159 matching lines @@
   if (found == blob_map_.end())
     return false;
   return found->second.flags & BEING_BUILT;
 }
 
 bool BlobStorageContext::IsUrlRegistered(const GURL& blob_url) {
   return public_blob_urls_.find(blob_url) != public_blob_urls_.end();
 }
 
 }  // namespace webkit_blob