Separate the text track container from the media controls

Source/core/html/track/TextTrackContainer.cpp

+/*
+ * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
+ * Copyright (C) 2012 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
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+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "core/html/track/TextTrackContainer.h"
+
+#include "core/html/HTMLVideoElement.h"
+#include "core/html/track/CueTimeline.h"
+#include "core/layout/LayoutTextTrackContainer.h"
+#include "core/layout/LayoutVideo.h"
+
+namespace blink {
+
+TextTrackContainer::TextTrackContainer(Document& document)
+    : HTMLDivElement(document)
+    , m_fontSize(0)
+{
+}
+
+PassRefPtrWillBeRawPtr<TextTrackContainer> TextTrackContainer::create(Document& document)
+{
+    RefPtrWillBeRawPtr<TextTrackContainer> element = adoptRefWillBeNoop(new TextTrackContainer(document));
+    element->setShadowPseudoId(AtomicString("-webkit-media-text-track-container", AtomicString::ConstructFromLiteral));

[philipj_slow, 2015/02/26 09:51:52]

Maybe this should still be under html/shadow/ because of this, but it seems to
me that this shadow id could be removed entirely by moving just a few things
from video::-webkit-media-text-track-container to C++. Maybe the color and
-webkit-user-select is enough. Not in this CL though.

+    return element.release();
+}
+
+LayoutObject* TextTrackContainer::createRenderer(const LayoutStyle&)
+{
+    return new LayoutTextTrackContainer(this);
+}
+
+void TextTrackContainer::updateDisplay(HTMLMediaElement& mediaElement)
+{
+    if (!mediaElement.closedCaptionsVisible()) {
+        removeChildren();
+        return;
+    }
+
+    // 1. If the media element is an audio element, or is another playback
+    // mechanism with no rendering area, abort these steps. There is nothing to
+    // render.
+    if (isHTMLAudioElement(mediaElement))
+        return;
+
+    // 2. Let video be the media element or other playback mechanism.
+    HTMLVideoElement& video = toHTMLVideoElement(mediaElement);
+
+    // 3. Let output be an empty list of absolutely positioned CSS block boxes.
+
+    // 4. If the user agent is exposing a user interface for video, add to
+    // output one or more completely transparent positioned CSS block boxes that
+    // cover the same region as the user interface.
+
+    // 5. If the last time these rules were run, the user agent was not exposing
+    // a user interface for video, but now it is, let reset be true. Otherwise,
+    // let reset be false.
+
+    // There is nothing to be done explicitly for 4th and 5th steps, as
+    // everything is handled through CSS. The caption box is on top of the
+    // controls box, in a container set with the -webkit-box display property.
+
+    // 6. Let tracks be the subset of video's list of text tracks that have as
+    // their rules for updating the text track rendering these rules for
+    // updating the display of WebVTT text tracks, and whose text track mode is
+    // showing or showing by default.
+    // 7. Let cues be an empty list of text track cues.
+    // 8. For each track track in tracks, append to cues all the cues from
+    // track's list of cues that have their text track cue active flag set.
+    CueList activeCues = video.cueTimeline().currentlyActiveCues();
+
+    // 9. If reset is false, then, for each text track cue cue in cues: if cue's
+    // text track cue display state has a set of CSS boxes, then add those boxes
+    // to output, and remove cue from cues.
+
+    // There is nothing explicitly to be done here, as all the caching occurs
+    // within the TextTrackCue instance itself. If parameters of the cue change,
+    // the display tree is cleared.
+
+    // 10. For each text track cue cue in cues that has not yet had
+    // corresponding CSS boxes added to output, in text track cue order, run the
+    // following substeps:
+    for (size_t i = 0; i < activeCues.size(); ++i) {
+        TextTrackCue* cue = activeCues[i].data();
+
+        ASSERT(cue->isActive());
+        if (!cue->track() || !cue->track()->isRendered() || !cue->isActive())
+            continue;
+
+        cue->updateDisplay(*this);
+    }
+
+    // 11. Return output.
+}
+
+void TextTrackContainer::updateSizes(HTMLMediaElement& mediaElement)
+{
+    if (!document().isActive())
+        return;
+
+    IntRect videoBox;
+
+    if (!mediaElement.renderer() || !mediaElement.renderer()->isVideo())
+        return;
+    videoBox = toLayoutVideo(mediaElement.renderer())->videoBox();

[philipj_slow, 2015/02/26 09:51:52]

I don't understand why the video size is used here when the whole element is
used for rendering. I filed a spec bug for a related issue:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=28105

I'm trying to change as little code as possible here, but if you think there
should be FIXMEs somewhere just say so.

[fs, 2015/02/26 12:30:51]

AFAIK though this is only used for the thing below - i.e. resolving a font-size
resembling "5vmin" - i.e. it's not actually used for cue positioning. (I half
wonder if it wouldn't be better to just push this into the LayoutObject, because
it seems like less like "hiding the ugly" - i.e. here it's less obvious that the
lifecycle is violated...)

[philipj_slow, 2015/02/27 07:13:51]

I've added a FIXME clarifying what I found odd here, also linking to the spec
bug.

+
+    if (m_videoDisplaySize == videoBox)
+        return;
+    m_videoDisplaySize = videoBox;
+
+    float smallestDimension = std::min(m_videoDisplaySize.size().height(), m_videoDisplaySize.size().width());
+
+    float fontSize = smallestDimension * 0.05f;
+    if (fontSize != m_fontSize) {
+        m_fontSize = fontSize;
+        setInlineStyleProperty(CSSPropertyFontSize, fontSize, CSSPrimitiveValue::CSS_PX);
+    }
+}
+
+} // namespace blink