Web Animations: Sort Players in DocumentTimeline::serviceAnimations

Source/core/animation/Player.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 18 matching lines @@
  */
 
 #include "config.h"
 #include "core/animation/Player.h"
 
 #include "core/animation/Animation.h"
 #include "core/animation/DocumentTimeline.h"
 
 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));
 }
 
 Player::Player(DocumentTimeline& timeline, TimedItem* content)
     : m_playbackRate(1)
     , m_startTime(nullValue())
     , m_holdTime(nullValue())
     , m_storedTimeLag(0)
     , m_content(content)
     , m_timeline(&timeline)
     , m_paused(false)
     , m_held(false)
     , m_isPausedForTesting(false)
     , m_outdated(false)
+    , m_sequenceNumber(nextSequenceNumber())
 {
     if (m_content) {
         if (m_content->player())
             m_content->player()->cancel();
         m_content->attach(this);
     }
 }
 
 Player::~Player()
 {
@@ skipping 227 matching lines @@
 void Player::cancel()
 {
     if (!m_content)
         return;
 
     ASSERT(m_content->player() == this);
     m_content->detach();
     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());
     updateTimingState(pauseTime);
     if (!m_isPausedForTesting && hasActiveAnimationsOnCompositor())
         toAnimation(m_content.get())->pauseAnimationForTestingOnCompositor(currentTime());
     m_isPausedForTesting = true;
     pause();
 }
 
 } // namespace