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

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index e5ee0cfc3ae607054efc2437abbda88c43ac6914..acc998601b15c07bf9bf9f9f4b83eb8959dbe647 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -1161,7 +1161,12 @@ int BrowserMainLoop::BrowserThreadsStarted() {
 
   {
     TRACE_EVENT0("startup", "BrowserThreadsStarted::Subsystem:MidiManager");
-    midi_manager_.reset(media::midi::MidiManager::Create());
+    media::midi::MidiManager::CreationOptions options;

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

I prefer to use
base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseAndroidMidiApi)
inside MidiManager(Android) so that we do not need to touch this file, and have
options for constructors.

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

Done.

+#if defined(OS_ANDROID)
+    options.set_use_native_midi_api(
+        parsed_command_line_.HasSwitch(switches::kUseAndroidMidiApi));
+#endif
+    midi_manager_.reset(media::midi::MidiManager::Create(options));
   }
 
 #if defined(OS_LINUX) && defined(USE_UDEV)