Web MIDI: implement MIDIInput

Source/core/dom/EventTarget.h

Index: Source/core/dom/EventTarget.h
diff --git a/Source/core/dom/EventTarget.h b/Source/core/dom/EventTarget.h
index 0aac8dc8c4d587fdc876cd7baa35ad8eaf5a4de5..f5d2eab4ded28b25d487d4ea86a25199edb18348 100644
--- a/Source/core/dom/EventTarget.h
+++ b/Source/core/dom/EventTarget.h
@@ -52,7 +52,7 @@ namespace WebCore {
     class IDBDatabase;
     class IDBRequest;
     class IDBTransaction;
-    class ScriptProcessorNode;
+    class MIDIInput;
     class MIDIPort;
     class MediaController;
     class MediaSource;
@@ -63,6 +63,7 @@ namespace WebCore {
     class Notification;
     class SVGElementInstance;
     class ScriptExecutionContext;
+    class ScriptProcessorNode;
     class SharedWorker;
     class SharedWorkerContext;
     class SourceBufferList;