Separate the text track container from the media controls

Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple 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
@@ skipping 3165 matching lines @@
         }
     }
     return false;
 }
 
 bool HTMLMediaElement::closedCaptionsVisible() const
 {
     return m_closedCaptionsVisible;
 }
 
+static void assertShadowRootChildren(ShadowRoot& shadowRoot)
+{
+#if ENABLE(ASSERT)
+    // There can be up to two children, either or both of the text
+    // track container and media controls. If both are present, the
+    // text track container must be the first child.
+    unsigned numberOfChildren = shadowRoot.countChildren();
+    ASSERT(numberOfChildren <= 2);
+    Node* firstChild = shadowRoot.firstChild();
+    Node* lastChild = shadowRoot.lastChild();
+    if (numberOfChildren == 1) {
+        ASSERT(firstChild->isTextTrackContainer() || firstChild->isMediaControls());
+    } else if (numberOfChildren == 2) {
+        ASSERT(firstChild->isTextTrackContainer());
+        ASSERT(lastChild->isMediaControls());
+    }
+#endif
+}
+
 TextTrackContainer& HTMLMediaElement::ensureTextTrackContainer()
 {
-    ensureMediaControls();
-    return *mediaControls()->textTrackContainer();
+    ShadowRoot& shadowRoot = ensureClosedShadowRoot();
+    assertShadowRootChildren(shadowRoot);
+
+    Node* firstChild = shadowRoot.firstChild();
+    if (firstChild && firstChild->isTextTrackContainer())
+        return toTextTrackContainer(*firstChild);
+
+    RefPtrWillBeRawPtr<TextTrackContainer> textTrackContainer = TextTrackContainer::create(document());
+
+    // The text track container should be inserted before the media controls,
+    // so that they are rendered behind them.
+    shadowRoot.insertBefore(textTrackContainer, firstChild);
+
+    assertShadowRootChildren(shadowRoot);
+
+    return *textTrackContainer;
 }
 
 void HTMLMediaElement::updateTextTrackDisplay()
 {
     WTF_LOG(Media, "HTMLMediaElement::updateTextTrackDisplay(%p)", this);
 
     ensureTextTrackContainer().updateDisplay(*this);
 }
 
 void HTMLMediaElement::setClosedCaptionsVisible(bool closedCaptionVisible)
@@ skipping 62 matching lines @@
 
     WTF_LOG(Media, "HTMLMediaElement::setShouldDelayLoadEvent(%p, %s)", this, boolString(shouldDelay));
 
     m_shouldDelayLoadEvent = shouldDelay;
     if (shouldDelay)
         document().incrementLoadEventDelayCount();
     else
         document().decrementLoadEventDelayCount();
 }
 
-
 MediaControls* HTMLMediaElement::mediaControls() const
 {
     if (ShadowRoot* shadowRoot = closedShadowRoot()) {
-        // Note that |shadowRoot->firstChild()| may be null.
-        return toMediaControls(shadowRoot->firstChild());
+        Node* lastChild = shadowRoot->lastChild();
+        if (lastChild && lastChild->isMediaControls())
+            return toMediaControls(lastChild);
     }
 
     return nullptr;
 }
 
 void HTMLMediaElement::ensureMediaControls()
 {
     if (mediaControls())
         return;
 
     RefPtrWillBeRawPtr<MediaControls> mediaControls = MediaControls::create(*this);
 
     mediaControls->reset();
     if (isFullscreen())
         mediaControls->enteredFullscreen();
 
-    ensureClosedShadowRoot().appendChild(mediaControls);
+    ShadowRoot& shadowRoot = ensureClosedShadowRoot();
+    assertShadowRootChildren(shadowRoot);
+
+    // The media controls should be inserted after the text track container,
+    // so that they are rendered in front of captions and subtitles.
+    shadowRoot.appendChild(mediaControls);
+
+    assertShadowRootChildren(shadowRoot);
 
     if (!shouldShowControls() || !inDocument())
         mediaControls->hide();
 }
 
 void HTMLMediaElement::configureMediaControls()
 {
     if (!inDocument()) {
         if (mediaControls())
             mediaControls()->hide();
@@ skipping 35 matching lines @@
         && m_haveVisibleTextTrack == haveVisibleTextTrack) {
         cueTimeline().updateActiveCues(currentTime());
         return;
     }
     m_haveVisibleTextTrack = haveVisibleTextTrack;
     m_closedCaptionsVisible = m_haveVisibleTextTrack;
 
     if (!m_haveVisibleTextTrack && !mediaControls())
         return;
 
-    ensureMediaControls();
-    mediaControls()->changedClosedCaptionsVisibility();
+    if (mediaControls())
+        mediaControls()->changedClosedCaptionsVisibility();
 
     cueTimeline().updateActiveCues(currentTime());
 
     // Note: The "time marches on" algorithm (updateActiveCues) runs the "rules
     // for updating the text track rendering" (updateTextTrackDisplay) only for
     // "affected tracks", i.e. tracks where the the active cues have changed.
     // This misses cues in tracks that changed mode between hidden and showing.
     // This appears to be a spec bug, which we work around here:
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=28236
     updateTextTrackDisplay();
@@ skipping 248 matching lines @@
 
 #if ENABLE(WEB_AUDIO)
 void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
 {
     if (!visitor->isAlive(m_audioSourceNode) && audioSourceProvider())
         audioSourceProvider()->setClient(nullptr);
 }
 #endif
 
 }