Web Animations: Sort Players in DocumentTimeline::serviceAnimations

Source/core/animation/Player.cpp

Index: Source/core/animation/Player.cpp
diff --git a/Source/core/animation/Player.cpp b/Source/core/animation/Player.cpp
index 35d2ed0f64897830a8f405a392f7fef49229b9ac..2276e1cc39ae43652166e5ba55f816612b63ddd2 100644
--- a/Source/core/animation/Player.cpp
+++ b/Source/core/animation/Player.cpp
@@ -36,6 +36,16 @@
 
 namespace WebCore {
 
+namespace {
+
+static unsigned nextSequenceNumber()
+{
+    static unsigned next = 0;
+    return ++next;
+}
+
+}
+
 PassRefPtr<Player> Player::create(DocumentTimeline& timeline, TimedItem* content)
 {
     return adoptRef(new Player(timeline, content));
@@ -52,6 +62,7 @@ Player::Player(DocumentTimeline& timeline, TimedItem* content)
     , m_held(false)
     , m_isPausedForTesting(false)
     , m_outdated(false)
+    , m_sequenceNumber(nextSequenceNumber())
 {
     if (m_content) {
         if (m_content->player())
@@ -299,6 +310,17 @@ void Player::cancel()
     m_content = nullptr;
 }
 
+bool Player::hasLowerPriority(Player* player1, Player* player2)
+{
+    if (player1->m_startTime < player2->m_startTime)
+        return true;
+    if (player1->m_startTime > player2->m_startTime)
+        return false;
+    if (isNull(player1->m_startTime) != isNull(player2->m_startTime))
+        return isNull(player1->m_startTime);
+    return player1->m_sequenceNumber < player2->m_sequenceNumber;
+}
+
 void Player::pauseForTesting(double pauseTime)
 {
     RELEASE_ASSERT(!paused());