Remove WebvttCssStyle.cascadeFrom()

It's not used. I was trying to work out how to correctly cascade my
text-combine-upright styling, but deleting the method seemed easier...

PiperOrigin-RevId: 287989480

library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCssStyle.java

@@ -287,37 +287,6 @@ public final class WebvttCssStyle {
     return fontSize;
     return fontSize;
   }
   }
 
 
-  public void cascadeFrom(WebvttCssStyle style) {
-    if (style.hasFontColor) {
-      setFontColor(style.fontColor);
-    }
-    if (style.bold != UNSPECIFIED) {
-      bold = style.bold;
-    }
-    if (style.italic != UNSPECIFIED) {
-      italic = style.italic;
-    }
-    if (style.fontFamily != null) {
-      fontFamily = style.fontFamily;
-    }
-    if (linethrough == UNSPECIFIED) {
-      linethrough = style.linethrough;
-    }
-    if (underline == UNSPECIFIED) {
-      underline = style.underline;
-    }
-    if (textAlign == null) {
-      textAlign = style.textAlign;
-    }
-    if (fontSizeUnit == UNSPECIFIED) {
-      fontSizeUnit = style.fontSizeUnit;
-      fontSize = style.fontSize;
-    }
-    if (style.hasBackgroundColor) {
-      setBackgroundColor(style.backgroundColor);
-    }
-  }
-
   private static int updateScoreForMatch(
   private static int updateScoreForMatch(
       int currentScore, String target, @Nullable String actual, int score) {
       int currentScore, String target, @Nullable String actual, int score) {
     if (target.isEmpty() || currentScore == -1) {
     if (target.isEmpty() || currentScore == -1) {