Improve caption button behavior for video player.

third_party/WebKit/Source/core/html/shadow/MediaControlElements.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.
@@ skipping 402 matching lines @@
 
 void MediaControlToggleClosedCaptionsButtonElement::updateDisplayType() {
   bool captionsVisible = mediaElement().textTracksVisible();
   setDisplayType(captionsVisible ? MediaHideClosedCaptionsButton
                                  : MediaShowClosedCaptionsButton);
 }
 
 void MediaControlToggleClosedCaptionsButtonElement::defaultEventHandler(
     Event* event) {
   if (event->type() == EventTypeNames::click) {
-    mediaControls().toggleTextTrackList();
+    if (mediaElement().textTracks()->length() == 1) {
+      // If only one track exists, toggle it on/off
+      if (mediaElement().textTracks()->hasShowingTracks()) {
+        mediaControls().disableShowingTextTracks();
+      } else {
+        mediaControls().showTextTrackAtIndex(0);
+      }
+    } else {
+      mediaControls().toggleTextTrackList();
+    }
+
     updateDisplayType();
     event->setDefaultHandled();
   }
 
   MediaControlInputElement::defaultEventHandler(event);
 }
 
 WebLocalizedString::Name
 MediaControlToggleClosedCaptionsButtonElement::getOverflowStringName() {
   return WebLocalizedString::OverflowMenuCaptions;
@@ skipping 15 matching lines @@
   return element;
 }
 
 void MediaControlTextTrackListElement::defaultEventHandler(Event* event) {
   if (event->type() == EventTypeNames::change) {
     // Identify which input element was selected and set track to showing
     Node* target = event->target()->toNode();
     if (!target || !target->isElementNode())
       return;
 
-    disableShowingTextTracks();
+    mediaControls().disableShowingTextTracks();
     int trackIndex =
         toElement(target)->getIntegralAttribute(trackIndexAttrName());
     if (trackIndex != trackIndexOffValue) {
       DCHECK_GE(trackIndex, 0);
-      showTextTrackAtIndex(trackIndex);
+      mediaControls().showTextTrackAtIndex(trackIndex);
       mediaElement().disableAutomaticTextTrackSelection();
     }
 
     event->setDefaultHandled();
   }
   MediaControlDivElement::defaultEventHandler(event);
 }
 
 void MediaControlTextTrackListElement::setVisible(bool visible) {
   if (visible) {
     setIsWanted(true);
     refreshTextTrackListMenu();
   } else {
     setIsWanted(false);
   }
 }
 
-void MediaControlTextTrackListElement::showTextTrackAtIndex(
-    unsigned indexToEnable) {
-  TextTrackList* trackList = mediaElement().textTracks();
-  if (indexToEnable >= trackList->length())
-    return;
-  TextTrack* track = trackList->anonymousIndexedGetter(indexToEnable);
-  if (track && track->canBeRendered())
-    track->setMode(TextTrack::showingKeyword());
-}
-
-void MediaControlTextTrackListElement::disableShowingTextTracks() {
-  TextTrackList* trackList = mediaElement().textTracks();
-  for (unsigned i = 0; i < trackList->length(); ++i) {
-    TextTrack* track = trackList->anonymousIndexedGetter(i);
-    if (track->mode() == TextTrack::showingKeyword())
-      track->setMode(TextTrack::disabledKeyword());
-  }
-}
-
 String MediaControlTextTrackListElement::getTextTrackLabel(TextTrack* track) {
-  if (!track)
+  if (!track) {
     return mediaElement().locale().queryString(
         WebLocalizedString::TextTracksOff);
+  }
 
   String trackLabel = track->label();
 
   if (trackLabel.isEmpty())
+    trackLabel = track->language();
+
+  if (trackLabel.isEmpty()) {
     trackLabel = String(mediaElement().locale().queryString(
-        WebLocalizedString::TextTracksNoLabel));
+        WebLocalizedString::TextTracksNoLabel,
+        String::number(track->trackIndex() + 1)));
+  }
 
   return trackLabel;
 }
 
 // TextTrack parameter when passed in as a nullptr, creates the "Off" list item
 // in the track list.
 Element* MediaControlTextTrackListElement::createTextTrackListItem(
     TextTrack* track) {
   int trackIndex = track ? track->trackIndex() : trackIndexOffValue;
   HTMLLabelElement* trackItem = HTMLLabelElement::create(document());
@@ skipping 504 matching lines @@
 MediaControlCurrentTimeDisplayElement*
 MediaControlCurrentTimeDisplayElement::create(MediaControls& mediaControls) {
   MediaControlCurrentTimeDisplayElement* element =
       new MediaControlCurrentTimeDisplayElement(mediaControls);
   element->setShadowPseudoId(
       AtomicString("-webkit-media-controls-current-time-display"));
   return element;
 }
 
 }  // namespace blink