Decouple MIDIAccess initialization from MIDIAccess class.

Source/modules/webmidi/MIDIAccessInitializer.h

+// 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 MIDIAccessInitializer_h
+#define MIDIAccessInitializer_h
+
+#include "bindings/v8/ScriptPromise.h"
+#include "modules/webmidi/MIDIAccessor.h"
+#include "modules/webmidi/MIDIAccessorClient.h"
+#include "modules/webmidi/MIDIOptions.h"
+#include "wtf/OwnPtr.h"
+
+namespace WebCore {
+
+class MIDIAccess;
+class ScriptState;
+class ScriptPromiseResolverWithContext;
+
+class MIDIAccessInitializer : public MIDIAccessorClient {
+public:
+    static PassOwnPtr<MIDIAccessInitializer> create(const MIDIOptions& options, MIDIAccess* access)
+    {
+        return adoptPtr(new MIDIAccessInitializer(options, access));
+    }
+    virtual ~MIDIAccessInitializer();
+
+    ScriptPromise initialize(ScriptState*);
+    void cancel();
+
+    bool hasPendingActivity() const { return m_state == Requesting; }
+
+    // MIDIAccessorClient
+    virtual void didAddInputPort(const String& id, const String& manufacturer, const String& name, const String& version) OVERRIDE;
+    virtual void didAddOutputPort(const String& id, const String& manufacturer, const String& name, const String& version) OVERRIDE;
+    virtual void didStartSession(bool success, const String& error, const String& message) OVERRIDE;
+    virtual void didReceiveMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp) OVERRIDE { }
+
+    void setSysexEnabled(bool value);
+    SecurityOrigin* securityOrigin() const;
+
+private:
+    class PostAction;
+    enum State {
+        Requesting,
+        Resolved,
+        Stopped,
+    };
+
+    MIDIAccessInitializer(const MIDIOptions&, MIDIAccess*);
+
+    ExecutionContext* executionContext() const;
+    void permissionDenied();
+    void doPostAction(State);
+
+    State m_state;
+    WeakPtrFactory<MIDIAccessInitializer> m_weakPtrFactory;
+    RefPtr<ScriptPromiseResolverWithContext> m_resolver;
+    OwnPtr<MIDIAccessor> m_accessor;
+    MIDIOptions m_options;
+    bool m_sysexEnabled;
+    // m_access has this object, so it's safe to have the raw pointer.
+    MIDIAccess* m_access;
+};
+
+} // namespace WebCore
+
+
+#endif // MIDIAccessInitializer_h