[WebMIDI] MIDIManager::create should return non-null object.

media/midi/midi_manager.cc

Index: media/midi/midi_manager.cc
diff --git a/media/midi/midi_manager.cc b/media/midi/midi_manager.cc
index 6d3f1d30b959139aaad7df5237090fc550b7f462..97678b3cc78aa73fc45409d8fa9e20d9b5a81e15 100644
--- a/media/midi/midi_manager.cc
+++ b/media/midi/midi_manager.cc
@@ -10,9 +10,34 @@
 namespace media {
 
 #if !defined(OS_MACOSX) && !defined(OS_WIN)
+namespace {
+
+class NullMIDIManager : public MIDIManager {

[Takashi Toyoshima, 2013/12/19 07:58:24]

How about just adding default implementations of Initialize(), and
DispatchSendMIDIDate() on MIDIManager class directly in midi_manager.h? Also
NOTREACHED() is needed inside DispatchSendMIDIData().

[yhirano, 2013/12/19 08:21:54]

Done.

+ public:
+  virtual ~NullMIDIManager();
+  virtual void DispatchSendMIDIData(MIDIManagerClient* client,
+                                    uint32 port_index,
+                                    const std::vector<uint8>& data,
+                                    double timestamp) OVERRIDE;
+  virtual bool Initialize() OVERRIDE;
+};
+
+NullMIDIManager::~NullMIDIManager() {}
+
+void NullMIDIManager::DispatchSendMIDIData(MIDIManagerClient* client,
+                                           uint32 port_index,
+                                           const std::vector<uint8>& data,
+                                           double timestamp) {}
+
+bool NullMIDIManager::Initialize() {
+  return false;
+}
+
+}  // namespace
+
 // TODO(crogers): implement MIDIManager for other platforms.
 MIDIManager* MIDIManager::Create() {
-  return NULL;
+  return new NullMIDIManager;
 }
 #endif