Web Animations: Throw exceptions for play/pause/reverse/finish with infinite end time

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

Index: third_party/WebKit/Source/core/animation/Animation.cpp
diff --git a/third_party/WebKit/Source/core/animation/Animation.cpp b/third_party/WebKit/Source/core/animation/Animation.cpp
index 197b921791673d6c093b822a87659bf8fcd47621..7c57d020d976a148e99b0d887bf99508f3c24e80 100644
--- a/third_party/WebKit/Source/core/animation/Animation.cpp
+++ b/third_party/WebKit/Source/core/animation/Animation.cpp
@@ -500,7 +500,7 @@ Animation::AnimationPlayState Animation::calculatePlayState()
     return Running;
 }
 
-void Animation::pause()
+void Animation::pause(ExceptionState& exceptionState)
 {
     if (m_paused)
         return;
@@ -509,6 +509,10 @@ void Animation::pause()
 
     double newCurrentTime = currentTimeInternal();
     if (calculatePlayState() == Idle) {
+        if (m_playbackRate < 0 && effectEnd() == std::numeric_limits<double>::infinity()) {
+            exceptionState.throwDOMException(InvalidStateError, "Cannot pause, Animation has infinite target effect end.");
+            return;
+        }
         newCurrentTime = m_playbackRate < 0 ? effectEnd() : 0;
     }
 
@@ -537,10 +541,16 @@ void Animation::unpauseInternal()
     setCurrentTimeInternal(currentTimeInternal(), TimingUpdateOnDemand);
 }
 
-void Animation::play()
+void Animation::play(ExceptionState& exceptionState)
 {
     PlayStateUpdateScope updateScope(*this, TimingUpdateOnDemand);
 
+    double currentTime = this->currentTimeInternal();
+    if (m_playbackRate < 0 && currentTime <= 0 && effectEnd() == std::numeric_limits<double>::infinity()) {
+        exceptionState.throwDOMException(InvalidStateError, "Cannot play reversed Animation with infinite target effect end.");
+        return;
+    }
+
     if (!playing()) {
         m_startTime = nullValue();
     }
@@ -550,8 +560,6 @@ void Animation::play()
         m_holdTime = 0;
     }
 
-    double currentTime = this->currentTimeInternal();
-
     m_playState = Unset;
     m_finished = false;
     unpauseInternal();
@@ -565,14 +573,14 @@ void Animation::play()
     }
 }
 
-void Animation::reverse()
+void Animation::reverse(ExceptionState& exceptionState)
 {
     if (!m_playbackRate) {
         return;
     }
 
     setPlaybackRateInternal(-m_playbackRate);
-    play();
+    play(exceptionState);
 }
 
 void Animation::finish(ExceptionState& exceptionState)