Revert of Run smooth scroll animations on the compositor when possible

third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp b/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
index 02635bed263571b4cead5bda12dee4e6c0350bf1..77996f3cb6d58c467fcd15caf227d5c546e7f80a 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
@@ -454,8 +454,6 @@
 {
     if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator())
         programmaticScrollAnimator->layerForCompositedScrollingDidChange(timeline);
-    if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
-        scrollAnimator->layerForCompositedScrollingDidChange(timeline);
 }
 
 bool ScrollableArea::scheduleAnimation()
@@ -471,8 +469,8 @@
 {
     bool requiresAnimationService = false;
     if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator()) {
-        scrollAnimator->tickAnimation(monotonicTime);
-        if (scrollAnimator->hasAnimationThatRequiresService())
+        scrollAnimator->serviceScrollAnimations();
+        if (scrollAnimator->hasRunningAnimation())
             requiresAnimationService = true;
     }
     if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator()) {
@@ -488,24 +486,18 @@
 {
     if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator())
         programmaticScrollAnimator->updateCompositorAnimations();
-
-    if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
-        scrollAnimator->updateCompositorAnimations();
 }
 
 void ScrollableArea::notifyCompositorAnimationFinished(int groupId)
 {
     if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator())
         programmaticScrollAnimator->notifyCompositorAnimationFinished(groupId);
-
-    if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
-        scrollAnimator->notifyCompositorAnimationFinished(groupId);
 }
 
 void ScrollableArea::cancelScrollAnimation()
 {
     if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
-        scrollAnimator->cancelAnimation();
+        scrollAnimator->cancelAnimations();
 }
 
 void ScrollableArea::cancelProgrammaticScrollAnimation()