[WebMIDI] Add "use-android-midi-api" flag for Android M+ devices.

media/midi/midi_manager_android.cc

Index: media/midi/midi_manager_android.cc
diff --git a/media/midi/midi_manager_android.cc b/media/midi/midi_manager_android.cc
index ce3db4aa3852895dfef8562b512c6d9d806eab00..fe27fdb5e38e6cc06069038295f7142385e96715 100644
--- a/media/midi/midi_manager_android.cc
+++ b/media/midi/midi_manager_android.cc
@@ -9,7 +9,7 @@
 namespace media {
 namespace midi {
 
-MidiManager* MidiManager::Create() {
+MidiManager* MidiManager::Create(const CreationOptions& options) {
   return new MidiManagerUsb(

[Takashi Toyoshima, 2015/08/12 04:39:47]

Could it be simply something like this?

if
(base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseAndroidMidiApi))
  return new MidiManagerAndroidNative()
else
  return new MidiManagerUsb(...)

[yhirano, 2015/08/12 05:37:05]

Done.

       scoped_ptr<UsbMidiDevice::Factory>(new UsbMidiDeviceFactoryAndroid));
 }