media: Support transporting 0-byte DecoderBuffer over mojo

media/mojo/common/mojo_decoder_buffer_converter.cc

Index: media/mojo/common/mojo_decoder_buffer_converter.cc
diff --git a/media/mojo/common/mojo_decoder_buffer_converter.cc b/media/mojo/common/mojo_decoder_buffer_converter.cc
index 0afbefc309feeafdc0ab44d62e0cd60516d51f2c..a7832bafda9827885c7bb2bfa79d33efee1bcd14 100644
--- a/media/mojo/common/mojo_decoder_buffer_converter.cc
+++ b/media/mojo/common/mojo_decoder_buffer_converter.cc
@@ -103,7 +103,8 @@ void MojoDecoderBufferReader::ReadDecoderBuffer(
       mojo_buffer.To<scoped_refptr<DecoderBuffer>>());
   DCHECK(media_buffer);
 
-  if (media_buffer->end_of_stream()) {
+  // A non-EOS buffer can have zero size. See http://crbug.com/663438
+  if (media_buffer->end_of_stream() || media_buffer->data_size() == 0) {

[chcunningham, 2016/11/08 22:00:38]

Could these be simplified to simply if (!media_buffer->data_size())?

[xhwang, 2016/11/08 22:13:51]

We can't call anything (including data_size()) if the buffer is EOS:

https://cs.chromium.org/chromium/src/media/base/decoder_buffer.h?rcl=0&l=106

     std::move(read_cb).Run(media_buffer);
     return;
   }
@@ -219,7 +220,8 @@ mojom::DecoderBufferPtr MojoDecoderBufferWriter::WriteDecoderBuffer(
   mojom::DecoderBufferPtr mojo_buffer =
       mojom::DecoderBuffer::From(media_buffer);
 
-  if (media_buffer->end_of_stream())
+  // A non-EOS buffer can have zero size. See http://crbug.com/663438
+  if (media_buffer->end_of_stream() || media_buffer->data_size() == 0)
     return mojo_buffer;
 
   // Serialize the data section of the DecoderBuffer into our pipe.