Web Animations: Fix effect change calculation when player is cancelled but not held

Review URL: https://codereview.chromium.org/235503010

git-svn-id: svn://svn.chromium.org/blink/trunk@171439 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/animation/AnimationPlayer.cpp

@@ -347,11 +347,13 @@ bool AnimationPlayer::update(UpdateReason reason)
 double AnimationPlayer::timeToEffectChange()
 {
     ASSERT(!m_outdated);
-    if (!m_content || m_held)
+    if (m_held || !hasStartTime())
         return std::numeric_limits<double>::infinity();
+    if (!m_content)
+        return -currentTime() / m_playbackRate;
     if (m_playbackRate > 0)
         return m_content->timeToForwardsEffectChange() / m_playbackRate;
-    return m_content->timeToReverseEffectChange() / std::abs(m_playbackRate);
+    return m_content->timeToReverseEffectChange() / -m_playbackRate;
 }
 
 void AnimationPlayer::cancel()

third_party/WebKit/Source/core/animation/AnimationPlayerTest.cpp

@@ -686,6 +686,26 @@ TEST_F(AnimationAnimationPlayerTest, TimeToNextEffectWhenPaused)
     EXPECT_EQ(std::numeric_limits<double>::infinity(), player->timeToEffectChange());
 }
 
+TEST_F(AnimationAnimationPlayerTest, TimeToNextEffectWhenCancelledBeforeStart)
+{
+    EXPECT_EQ(0, player->timeToEffectChange());
+    player->setCurrentTime(-8);
+    player->setPlaybackRate(2);
+    player->cancel();
+    player->update(AnimationPlayer::UpdateOnDemand);
+    EXPECT_EQ(4, player->timeToEffectChange());
+}
+
+TEST_F(AnimationAnimationPlayerTest, TimeToNextEffectWhenCancelledBeforeStartReverse)
+{
+    EXPECT_EQ(0, player->timeToEffectChange());
+    player->setCurrentTime(9);
+    player->setPlaybackRate(-3);
+    player->cancel();
+    player->update(AnimationPlayer::UpdateOnDemand);
+    EXPECT_EQ(3, player->timeToEffectChange());
+}
+
 TEST_F(AnimationAnimationPlayerTest, AttachedAnimationPlayers)
 {
     RefPtr<Element> element = document->createElement("foo", ASSERT_NO_EXCEPTION);