IndexedDB: Fixed support for empty blobs.

net/base/upload_data_stream.cc

Index: net/base/upload_data_stream.cc
diff --git a/net/base/upload_data_stream.cc b/net/base/upload_data_stream.cc
index 936c9128833017c91e5738b4338974748ec7af4e..43216d4aa34698f53a20ecea17df34439d3888bb 100644
--- a/net/base/upload_data_stream.cc
+++ b/net/base/upload_data_stream.cc
@@ -43,8 +43,8 @@ int UploadDataStream::Read(IOBuffer* buf,
                            const CompletionCallback& callback) {
   DCHECK(!callback.is_null() || IsInMemory());
   DCHECK(initialized_successfully_);
-  DCHECK_GT(buf_len, 0);
-  if (is_eof_)
+  DCHECK_GE(buf_len, 0);
+  if (!buf_len || is_eof_)

[michaeln, 2015/03/09 21:15:18]

This is a little troublesome because generally reading 0 bytes back indicates
eof. How is this hit by the tests?

[mmenke, 2015/03/09 21:20:09]

Can we instead set is_eof_ to true in SetSize, if size is 0?  And have a net/
test for that case, as we apparently don't have one currently.

In fact, this fix and that change should be in a separate CL.  I'm happy to
review it.

[mmenke, 2015/03/09 21:22:41]

The test should be in elements_upload_data_stream_unittest.cc (We don't
currently test this class independently, though we probably should).

[cmumford, 2015/03/09 22:05:11]

Reverted this change as suggested.

     return 0;
   int result = ReadInternal(buf, buf_len);
   if (result == ERR_IO_PENDING) {