Web MIDI: introduce pending client count limit to start sessions

media/midi/midi_manager.h

Index: media/midi/midi_manager.h
diff --git a/media/midi/midi_manager.h b/media/midi/midi_manager.h
index 46602c1df16bef9d293e99808bf81ec7747bb106..7ac2235b275454988b152a742699819b319dc447 100644
--- a/media/midi/midi_manager.h
+++ b/media/midi/midi_manager.h
@@ -55,13 +55,15 @@ class MEDIA_EXPORT MidiManagerClient {
 // Manages access to all MIDI hardware.
 class MEDIA_EXPORT MidiManager {
  public:
-  // The constructor and the destructor will be called on the CrBrowserMain
-  // thread.
-  static MidiManager* Create();
+  static const size_t kMaxPendingClientCount = 128;
 
   MidiManager();
   virtual ~MidiManager();
 
+  // The constructor and the destructor will be called on the CrBrowserMain
+  // thread.
+  static MidiManager* Create();
+
   // A client calls StartSession() to receive and send MIDI data.
   // If the session is ready to start, the MIDI system is lazily initialized
   // and the client is registered to receive MIDI data.