Introduce MIDIInputMap and MIDIOutputMap.

Source/modules/webmidi/MIDIInputMap.h

Index: Source/modules/webmidi/MIDIInputMap.h
diff --git a/Source/modules/webmidi/MIDIInputMap.h b/Source/modules/webmidi/MIDIInputMap.h
new file mode 100644
index 0000000000000000000000000000000000000000..a1c8b8b8f183feff10ebad2be3f9959eba9d8706
--- /dev/null
+++ b/Source/modules/webmidi/MIDIInputMap.h
@@ -0,0 +1,25 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MIDIInputMap_h
+#define MIDIInputMap_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "modules/webmidi/MIDIInput.h"
+#include "modules/webmidi/MIDIPortMap.h"
+
+namespace blink {
+
+class ScriptState;
+
+class MIDIInputMap : public MIDIPortMap<MIDIInput>, public ScriptWrappable {
+public:
+    explicit MIDIInputMap(const HeapHashMap<String, Member<MIDIInput> >);
+
+    ScriptValue getForBinding(ScriptState*, const String& id);
+};
+
+} // namespace blink
+
+#endif