Move automatic text track selection code to AutomaticTrackSelection helper

Source/core/html/track/AutomaticTrackSelection.h

+// Copyright 2015 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 AutomaticTrackSelection_h
+#define AutomaticTrackSelection_h
+
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class TextTrackList;
+class TrackGroup;
+
+class AutomaticTrackSelection {
+    STACK_ALLOCATED();
+public:
+    struct Configuration {
+        Configuration()
+            : disableCurrentlyEnabledTracks(false)
+            , forceEnableSubtitleOrCaptionTrack(false) { }
+
+        bool disableCurrentlyEnabledTracks;
+        bool forceEnableSubtitleOrCaptionTrack;
+    };
+
+    AutomaticTrackSelection(const Configuration&);
+
+    void perform(TextTrackList&);
+
+private:
+    void performAutomaticTextTrackSelection(const TrackGroup&);
+    void enableDefaultMetadataTextTracks(const TrackGroup&);
+
+    const Configuration m_configuration;
+};
+
+} // namespace blink
+
+#endif // AutomaticTrackSelection_h