[Sketch] Animations: Torpedo the old intrusive animation system.

Source/core/page/scrolling/ScrollingCoordinator.cpp

Index: Source/core/page/scrolling/ScrollingCoordinator.cpp
diff --git a/Source/core/page/scrolling/ScrollingCoordinator.cpp b/Source/core/page/scrolling/ScrollingCoordinator.cpp
index 1ff8a2733a36edb460748df3160cfd8e7cca2e98..d2968e4a5166755e97d25e47992d98fb705e6a9f 100644
--- a/Source/core/page/scrolling/ScrollingCoordinator.cpp
+++ b/Source/core/page/scrolling/ScrollingCoordinator.cpp
@@ -95,12 +95,10 @@ ScrollingCoordinator::ScrollingCoordinator(Page* page)
     , m_wasFrameScrollable(false)
     , m_lastMainThreadScrollingReasons(0)
 {
-    if (RuntimeEnabledFeatures::compositorAnimationTimelinesEnabled() && Platform::current()->compositorSupport()) {
-        ASSERT(m_page);
-        ASSERT(m_page->mainFrame()->isLocalFrame());
-        m_programmaticScrollAnimatorTimeline = adoptPtr(Platform::current()->compositorSupport()->createAnimationTimeline());
-        m_page->chrome().client().attachCompositorAnimationTimeline(m_programmaticScrollAnimatorTimeline.get(), toLocalFrame(m_page->mainFrame()));
-    }
+    ASSERT(m_page);
+    ASSERT(m_page->mainFrame()->isLocalFrame());
+    m_programmaticScrollAnimatorTimeline = adoptPtr(Platform::current()->compositorSupport()->createAnimationTimeline());
+    m_page->chrome().client().attachCompositorAnimationTimeline(m_programmaticScrollAnimatorTimeline.get(), toLocalFrame(m_page->mainFrame()));
 }
 
 ScrollingCoordinator::~ScrollingCoordinator()
@@ -713,12 +711,8 @@ void ScrollingCoordinator::setShouldUpdateScrollLayerPositionOnMainThread(MainTh
 void ScrollingCoordinator::willBeDestroyed()
 {
     ASSERT(m_page);
-
-    if (m_programmaticScrollAnimatorTimeline) {
-        ASSERT(m_page->mainFrame()->isLocalFrame());
-        m_page->chrome().client().detachCompositorAnimationTimeline(m_programmaticScrollAnimatorTimeline.get(), toLocalFrame(m_page->mainFrame()));
-        m_programmaticScrollAnimatorTimeline.clear();
-    }
+    ASSERT(m_page->mainFrame()->isLocalFrame());
+    m_page->chrome().client().detachCompositorAnimationTimeline(m_programmaticScrollAnimatorTimeline.get(), toLocalFrame(m_page->mainFrame()));
 
     m_page = nullptr;
     for (const auto& scrollbar : m_horizontalScrollbars)