MSE: Implement TrackDefaultList object

Source/modules/mediasource/TrackDefaultList.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 TrackDefaultList_h
+#define TrackDefaultList_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "modules/mediasource/TrackDefault.h"
+#include "platform/heap/Handle.h"
+#include "wtf/text/AtomicStringHash.h"
+#include "wtf/text/StringHash.h"
+
+namespace blink {
+
+class ExceptionState;
+
+class TrackDefaultList final : public GarbageCollected<TrackDefaultList>, public ScriptWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    static TrackDefaultList* create(const HeapVector<Member<TrackDefault>>&, ExceptionState&);
+
+    // Implement the IDL
+    unsigned length() const { return m_trackDefaults.size(); }
+    TrackDefault* item(unsigned) const;
+
+    void trace(Visitor*);
+
+private:
+    typedef std::pair<AtomicString, String> TypeAndID;

[sof, 2014/12/12 09:37:00]

nit: switch to the du jour 'using'?

[wolenetz, 2014/12/12 19:18:31]

I assume you mean:
using std::pair;
typedef pair<AtomicString, String> TypeAndID;

However, that actually adds a line of code, and only removes std:: from one
location.
I think I'm missing what you really mean. Please clarify.

[wolenetz, 2014/12/12 21:48:05]

Done.

+    typedef HeapHashMap<TypeAndID, Member<TrackDefault>> TypeAndIDToTrackDefaultMap;
+
+    TrackDefaultList(const HeapVector<Member<TrackDefault>>&, const TypeAndIDToTrackDefaultMap&);
+
+    const HeapVector<Member<TrackDefault>> m_trackDefaults;
+
+    // HashMapped index of |m_trackDefaults| for lookup by unique <type, byteStreamTrackID>.
+    const TypeAndIDToTrackDefaultMap m_typeAndIDToTrackDefaultMap;

[philipj_slow, 2014/12/12 20:25:21]

This is never used, just traced. I guess a bunch of things can be removed from
this header as a result.

[wolenetz, 2014/12/12 21:48:05]

Done.

+};
+
+} // namespace blink
+
+#endif // TrackDefaultList_h