subtitle tracks with no srclang show up as " (label)" instead of just "label"

https://bugs.webkit.org/show_bug.cgi?id=290226

Reviewed by Eric Carlson.

* Source/WebCore/page/CaptionUserPreferencesMediaAF.cpp:
(WebCore::trackDisplayName):
Only use the localized format string if both parts are valid.

* Source/WebCore/page/CaptionUserPreferences.cpp:
(WebCore::trackDisplayName):
Strip any leading/trailing whitespace from the `label` before deciding whether to use it.

* LayoutTests/media/modern-media-controls/tracks-support/sorted-by-user-preferred-languages.html:
* LayoutTests/media/modern-media-controls/tracks-support/sorted-by-user-preferred-languages-expected.txt:

Canonical link: https://commits.webkit.org/292577@main

Author: dcrousso

LayoutTests/media/modern-media-controls/tracks-support/sorted-by-user-preferred-languages-expected.txt

@@ -15,6 +15,7 @@ Subtitles: [
   "Spanish Captions",
   "Spanish",
   "Spanish Descriptions",
+  "no-srclang",
   "Chinese (China mainland)",
   "French Captions (label-fr)",
   "French (label-fr)",

LayoutTests/media/modern-media-controls/tracks-support/sorted-by-user-preferred-languages.html

@@ -16,7 +16,8 @@
     <track src="../../lorem-ipsum.vtt" kind="subtitles"    srclang="fr" label="label-fr">
     <track src="../../lorem-ipsum.vtt" kind="descriptions" srclang="es" label="Descriptions">
     <track src="../../lorem-ipsum.vtt" kind="captions"     srclang="es">
-    <track src="../../lorem-ipsum.vtt" kind="subtitles"    srclang="es">
+    <track src="../../lorem-ipsum.vtt" kind="subtitles"    srclang="es" label=" ">
+    <track src="../../lorem-ipsum.vtt" kind="subtitles"                 label="no-srclang">
     <track src="../../lorem-ipsum.vtt" kind="subtitles"    srclang="zh-CN">
 </video>
 <script type="text/javascript">

Source/WebCore/page/CaptionUserPreferences.cpp

@@ -217,11 +217,11 @@ static String trackDisplayName(TextTrack* track)
     if (track == &TextTrack::captionMenuAutomaticItem())
         return textTrackAutomaticMenuItemText();
 
-    if (track->label().isEmpty() && track->validBCP47Language().isEmpty())
-        return trackNoLabelText();
-    if (!track->label().isEmpty())
+    if (auto label = track->label().string().trim(isASCIIWhitespace); !label.isEmpty())
         return track->label();
-    return track->validBCP47Language();
+    if (auto languageIdentifier = track->validBCP47Language(); !languageIdentifier.isEmpty())
+        return languageIdentifier;
+    return trackNoLabelText();
 }
 
 String CaptionUserPreferences::displayNameForTrack(TextTrack* track) const
@@ -286,11 +286,11 @@ Vector<RefPtr<TextTrack>> CaptionUserPreferences::sortedTrackListForMenu(TextTra
 
 static String trackDisplayName(AudioTrack* track)
 {
-    if (track->label().isEmpty() && track->validBCP47Language().isEmpty())
-        return trackNoLabelText();
-    if (!track->label().isEmpty())
+    if (auto label = track->label().string().trim(isASCIIWhitespace); !label.isEmpty())
         return track->label();
-    return track->validBCP47Language();
+    if (auto languageIdentifier = track->validBCP47Language(); !languageIdentifier.isEmpty())
+        return languageIdentifier;
+    return trackNoLabelText();
 }
 
 String CaptionUserPreferences::displayNameForTrack(AudioTrack* track) const

Source/WebCore/page/CaptionUserPreferencesMediaAF.cpp

@@ -735,7 +735,7 @@ static String trackDisplayName(const TrackBase& track)
 
     String result;
 
-    String label = track.label();
+    String label = track.label().string().trim(isASCIIWhitespace);
     String trackLanguageIdentifier = track.validBCP47Language();
 
     auto preferredLanguages = userPreferredLanguages(ShouldMinimizeLanguages::No);
@@ -761,8 +761,12 @@ static String trackDisplayName(const TrackBase& track)
 
         result = addTrackKindDisplayNameIfNeeded(track, result);
 
-        if (!label.isEmpty() && !result.contains(label))
-            result = addTrackLabelAsSuffix(result, label);
+        if (!label.isEmpty()) {
+            if (result.isEmpty())
+                result = label;
+            else if (!result.contains(label))
+                result = addTrackLabelAsSuffix(result, label);
+        }
     }
 
     if (result.isEmpty())