2018-05-04  Antoine Quint  <graouts@apple.com>

        REGRESSION (r230574): Interrupted hardware transitions don't behave correctly

        https://bugs.webkit.org/show_bug.cgi?id=185299

        <rdar://problem/39630230>

        Reviewed by NOBODY (OOPS!).

        In r230574, the fix for webkit.org/b/184518, we changed the processing order in GraphicsLayerCA::updateAnimations() to first

        process m_uncomittedAnimations and then m_animationsToProcess, so we are guaranteed animations exist before we attempt to pause

        or seek them. This broke interrupting and resuming hardware animations (such as an interrupted CSS Transition or an animation

        running in a non-visible tab) since a pause operation recorded _before_ an animation was added would be paused anyway since

        the animation was now first added, and then paused. The fix is simply to clear any pending AnimationProcessingAction for a

        newly-uncommitted animation.

        No new tests since there is no existing mechanism that allows to test this behavior since this is about the internal state of

        an animation performed by Core Animation.

        * platform/graphics/ca/GraphicsLayerCA.cpp:

        (WebCore::GraphicsLayerCA::createAnimationFromKeyframes):

        (WebCore::GraphicsLayerCA::appendToUncommittedAnimations):

        (WebCore::GraphicsLayerCA::createTransformAnimationsFromKeyframes):

        * platform/graphics/ca/GraphicsLayerCA.h:

        (WebCore::GraphicsLayerCA::LayerPropertyAnimation::LayerPropertyAnimation):

void GraphicsLayerCA::appendToUncommittedAnimations(LayerPropertyAnimation&& animation)

{

    // Since we're adding a new animation, make sure we clear any pending AnimationProcessingAction for this animation

    // as these are applied after we've committed new animations.

    m_animationsToProcess.remove(animation.m_name);

    m_uncomittedAnimations.append(WTFMove(animation));

}

    // This represents the animation of a single property. There may be multiple transform animations for

    // a single transition or keyframe animation, so index is used to distinguish these.

    struct LayerPropertyAnimation {

        LayerPropertyAnimation(Ref<PlatformCAAnimation>&& caAnimation, const String& animationName, AnimatedPropertyID property, int index, int subIndex, Seconds timeOffset)

            : m_animation(WTFMove(caAnimation))

            , m_name(animationName)

            , m_property(property)

            , m_index(index)

            , m_subIndex(subIndex)

            , m_timeOffset(timeOffset)

        { }

        RefPtr<PlatformCAAnimation> m_animation;

        String m_name;

        AnimatedPropertyID m_property;

        int m_index;

        int m_subIndex;

        Seconds m_timeOffset;

    };

    void appendToUncommittedAnimations(LayerPropertyAnimation&&);