From dd3597c2c19c900b4de7bccb955c9c3729973dda Mon Sep 17 00:00:00 2001
From: ibaker <ibaker@google.com>
Date: Mon, 29 Mar 2021 10:47:56 +0100
Subject: [PATCH] Document that the order of cues passed to TextOutput is
 important

Fix WebViewSubtitleOutput to respect this (CanvasSubtitleOutput already
does).

Issue: #8704
PiperOrigin-RevId: 365534018
---
 .../java/com/google/android/exoplayer2/text/TextOutput.java    | 3 +++
 .../google/android/exoplayer2/ui/WebViewSubtitleOutput.java    | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/library/common/src/main/java/com/google/android/exoplayer2/text/TextOutput.java b/library/common/src/main/java/com/google/android/exoplayer2/text/TextOutput.java
index a039255fa9..6d66dadbfc 100644
--- a/library/common/src/main/java/com/google/android/exoplayer2/text/TextOutput.java
+++ b/library/common/src/main/java/com/google/android/exoplayer2/text/TextOutput.java
@@ -25,6 +25,9 @@ public interface TextOutput {
   /**
    * Called when there is a change in the {@link Cue Cues}.
    *
+   * <p>{@code cues} is in ascending order of priority. If any of the cue boxes overlap when
+   * displayed, the {@link Cue} nearer the end of the list should be shown on top.
+   *
    * @param cues The {@link Cue Cues}. May be empty.
    */
   void onCues(List<Cue> cues);
diff --git a/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java b/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java
index f3de4298a5..7a67b85920 100644
--- a/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java
+++ b/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java
@@ -278,6 +278,7 @@ import java.util.Map;
               Util.formatInvariant(
                   "<div style='"
                       + "position:absolute;"
+                      + "z-index:%s;"
                       + "%s:%.2f%%;"
                       + "%s:%s;"
                       + "%s:%s;"
@@ -287,6 +288,7 @@ import java.util.Map;
                       + "background-color:%s;"
                       + "transform:translate(%s%%,%s%%);"
                       + "'>",
+                  /* z-index */ i,
                   positionProperty,
                   positionPercent,
                   lineProperty,