Web MIDI: fix multi-threading problem around message buffer handling

content/renderer/media/midi_message_filter.cc

Index: content/renderer/media/midi_message_filter.cc
diff --git a/content/renderer/media/midi_message_filter.cc b/content/renderer/media/midi_message_filter.cc
index 39f391494f00a24a99fdb89ba3270d1edbb55e65..9eee3a317278e07a9d07766b8a48cc1a32e3a022 100644
--- a/content/renderer/media/midi_message_filter.cc
+++ b/content/renderer/media/midi_message_filter.cc
@@ -187,7 +187,7 @@ void MIDIMessageFilter::HandleDataReceived(int port,
 #endif
 }
 
-void MIDIMessageFilter::SendMIDIData(int port,
+void MIDIMessageFilter::SendMIDIData(unsigned int port,

[palmer, 2013/08/22 18:31:26]

Yeah, harmonize these types. What is the actual range of values for ports? I
assume that is determined in the MIDI standard?

[Takashi Toyoshima, 2013/08/23 02:39:15]

This parameter doesn't depend on MIDI spec. Because this is the number of
devices which is connected to the operating system. In the real situation,
uint16 may be enough. But, size_t is good to be used for the number the range is
ambiguous.

                                      const uint8* data,
                                      size_t length,
                                      double timestamp) {
@@ -203,7 +203,7 @@ void MIDIMessageFilter::SendMIDIData(int port,
                  port, v, timestamp));
 }
 
-void MIDIMessageFilter::SendMIDIDataOnIOThread(int port,
+void MIDIMessageFilter::SendMIDIDataOnIOThread(size_t port,
                                                const std::vector<uint8>& data,
                                                double timestamp) {
   size_t n = data.size();