Cherry-pick 379505f. rdar://122584350

    Subtitle size is enlarged in Full screen
    https://bugs.webkit.org/show_bug.cgi?id=269085
    rdar://122584350

    Reviewed by Jer Noble.

    Webkit-media-text-track-display pseudo-elements should have a font size unit of CQMIN instead of CQH. CQMIN will be calculated to be CQW if the width of the video element is shorter than the height, or CQH vice versa. This creates a more appropriate font size.

    * Source/WebCore/html/track/VTTCue.cpp:
    (WebCore::VTTCueBox::applyCSSProperties):

    Canonical link: https://commits.webkit.org/274480@main

Identifier: 272448.552@safari-7618.1.15.10-branch

Source/WebCore/html/track/VTTCue.cpp

@@ -257,7 +257,7 @@ void VTTCueBox::applyCSSProperties()
     // The font shorthand property on the (root) list of WebVTT Node Objects
     // must be set to 5vh sans-serif. [CSS-VALUES]
     // NOTE: We use 'cqh' rather than 'vh' as the video element is not a proper viewport.
-    setInlineStyleProperty(CSSPropertyFontSize, cue->fontSize(), CSSUnitType::CSS_CQH, cue->fontSizeIsImportant());
+    setInlineStyleProperty(CSSPropertyFontSize, cue->fontSize(), CSSUnitType::CSS_CQMIN, cue->fontSizeIsImportant());
 
     if (!cue->snapToLines()) {
         setInlineStyleProperty(CSSPropertyWhiteSpaceCollapse, CSSValuePreserve);