implement QVideoProbe for iOS camera

This commit allows to use QVideoProbe for QCamera on iOS.
The logic for the implementation is taken from the Android plugin.

[ChangeLog][Platform Specific Changes][iOS]
QVideoProbe support is implemented for QCamera on iOS

Change-Id: I1db50defa8518287c4f1f3cc6602881702a95849
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>

src/plugins/avfoundation/camera/avfmediavideoprobecontrol.h

@@ -0,0 +1,54 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia. For licensing terms and
+** conditions see http://qt.digia.com/licensing. For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights. These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef AVFMEDIAVIDEOPROBECONTROL_H
+#define AVFMEDIAVIDEOPROBECONTROL_H
+
+#include <qmediavideoprobecontrol.h>
+
+QT_BEGIN_NAMESPACE
+
+class AVFMediaVideoProbeControl : public QMediaVideoProbeControl
+{
+    Q_OBJECT
+public:
+    explicit AVFMediaVideoProbeControl(QObject *parent = 0);
+    ~AVFMediaVideoProbeControl();
+
+    void newFrameProbed(const QVideoFrame& frame);
+
+};
+
+QT_END_NAMESPACE
+
+#endif // AVFMEDIAVIDEOPROBECONTROL_H