Initial implementation of AudioTrack, AudioTrackList, VideoTrack, and VideoTrackList.

Source/core/html/track/TrackBaseList.cpp

+// 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.
+
+#include "config.h"
+#include "core/html/track/TrackBaseList.h"
+
+#include "core/events/GenericEventQueue.h"
+#include "core/html/track/TrackBase.h"
+#include "core/html/track/TrackEvent.h"
+#include "platform/Logging.h"
+
+namespace WebCore {
+
+TrackBaseList::TrackBaseList(HTMLMediaElement* mediaElement)
+    : ActiveDOMObject(mediaElement->executionContext())
+    , m_shutdown(false)
+    , m_asyncEventQueue(GenericEventQueue::create(this))
+{
+    ASSERT(mediaElement);
+}
+
+TrackBaseList::~TrackBaseList()
+{
+    ASSERT(m_shutdown);
+    ASSERT(m_tracks.isEmpty());
+}
+
+void TrackBaseList::shutdown()
+{
+    m_shutdown = true;
+    removeAll();
+    m_asyncEventQueue->close();
+}
+
+TrackBase* TrackBaseList::getByIndex(unsigned index) const
+{
+    if (index >= m_tracks.size())
+        return 0;

[philipj_slow, 2014/03/13 10:00:04]

This seems unreachable in the current code, ASSERT(index < m_tracks.size()) and
return a reference instead?

+
+    return m_tracks[index].get();

[philipj_slow, 2014/03/13 10:00:04]

Any reason to not return RefPtr<TrackBase> here and in the rest of this API? (I
don't know what the convention is, just asking to learn.)

[acolwell GONE FROM CHROMIUM, 2014/03/18 22:02:15]

The RefPtr is not used to avoid an unnecessary ref()/deref() pair. I can change
it to PassRefPtr<> though so I'll do that.

[philipj_slow, 2014/03/20 16:17:40]

Thanks, that's something I should keep in mind as well I guess.

+}
+
+TrackBase* TrackBaseList::getById(const AtomicString& id) const
+{
+    for (unsigned i = 0; i < m_tracks.size(); ++i) {
+        if (m_tracks[i]->id() == id)
+            return m_tracks[i].get();
+    }
+
+    return 0;
+}
+
+unsigned TrackBaseList::getIndex(const AtomicString& id) const

[philipj_slow, 2014/03/13 10:00:04]

This is only used by VideoTrackList::trackSelected and it seems like if the
layering for handling enabled/selected changes were different, this could take a
TrackBase* instead of an id, or possibly not be needed at all.

+{
+    for (unsigned i = 0; i < m_tracks.size(); ++i) {
+        if (m_tracks[i]->id() == id)
+            return i;
+    }
+
+    ASSERT_NOT_REACHED();
+    return 0;
+}
+
+ExecutionContext* TrackBaseList::executionContext() const
+{
+    return ActiveDOMObject::executionContext();
+}
+
+bool TrackBaseList::hasPendingActivity() const
+{
+    return !m_shutdown || m_asyncEventQueue->hasPendingEvents() || ActiveDOMObject::hasPendingActivity();
+}
+
+void TrackBaseList::stop()
+{
+    shutdown();
+}
+
+void TrackBaseList::add(TrackBase* track)

[philipj_slow, 2014/03/13 10:00:04]

The callers have a RefPtr and call get(), use PassRefPtr here instead?

[acolwell GONE FROM CHROMIUM, 2014/03/18 22:02:15]

Done.

+{
+    m_tracks.append(track);
+
+    scheduleTrackEvent(EventTypeNames::addtrack, track);
+}
+
+void TrackBaseList::remove(const String& id)
+{
+    for (unsigned i = 0; i < m_tracks.size(); ++i) {
+        if (m_tracks[i]->id() == id) {
+            m_tracks[i]->setMediaElement(0);
+            scheduleTrackEvent(EventTypeNames::removetrack, m_tracks[i]);
+            m_tracks.remove(i);
+            return;
+        }
+    }
+}
+
+void TrackBaseList::removeAll()
+{
+    for (unsigned i = 0; i < m_tracks.size(); ++i)
+        m_tracks[i]->setMediaElement(0);
+
+    m_tracks.clear();
+}
+
+void TrackBaseList::scheduleChangeEvent()
+{
+    WTF_LOG(Media, "TrackBaseList::scheduleChangeEvent() : %p", this);
+    EventInit initializer;
+    initializer.bubbles = false;
+    initializer.cancelable = false;
+    m_asyncEventQueue->enqueueEvent(Event::create(EventTypeNames::change, initializer));
+}
+
+void TrackBaseList::scheduleTrackEvent(const AtomicString& eventName, PassRefPtr<TrackBase> track)

[philipj_slow, 2014/03/13 10:00:04]

Tests that verify that isTrusted is true for these events would be nice,
wherever this ends up:
http://www.whatwg.org/specs/web-apps/current-work/multipage/infrastructure.ht...

+{
+    WTF_LOG(Media, "TrackBaseList::scheduleTrackEvent(%s) : %p", eventName.string().ascii().data(), this);
+    TrackEventInit initializer;
+    initializer.track = track;
+    initializer.bubbles = false;
+    initializer.cancelable = false;
+
+    m_asyncEventQueue->enqueueEvent(TrackEvent::create(eventName, initializer));
+}
+
+}