Account for scroll origin in scroll animators.

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

Index: third_party/WebKit/Source/platform/scroll/ProgrammaticScrollAnimator.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ProgrammaticScrollAnimator.cpp b/third_party/WebKit/Source/platform/scroll/ProgrammaticScrollAnimator.cpp
index 99f58fd7b3390ca1aa25e12abf734218f3a4dfea..437bee38681c0dd871c04818285008f2721062fb 100644
--- a/third_party/WebKit/Source/platform/scroll/ProgrammaticScrollAnimator.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ProgrammaticScrollAnimator.cpp
@@ -56,7 +56,7 @@ void ProgrammaticScrollAnimator::animateToOffset(FloatPoint offset)
     m_startTime = 0.0;
     m_targetOffset = offset;
     m_animationCurve = adoptPtr(CompositorFactory::current().createScrollOffsetAnimationCurve(
-        m_targetOffset,
+        compositorOffsetFromBlinkOffset(m_targetOffset),
         CompositorAnimationCurve::TimingFunctionTypeEaseInOut,
         CompositorScrollOffsetAnimationCurve::ScrollDurationDeltaBased));
 
@@ -83,7 +83,7 @@ void ProgrammaticScrollAnimator::tickAnimation(double monotonicTime)
         m_startTime = monotonicTime;
     double elapsedTime = monotonicTime - m_startTime;
     bool isFinished = (elapsedTime > m_animationCurve->duration());
-    FloatPoint offset = m_animationCurve->getValue(elapsedTime);
+    FloatPoint offset = blinkOffsetFromCompositorOffset(m_animationCurve->getValue(elapsedTime));
     notifyPositionChanged(IntPoint(offset.x(), offset.y()));
 
     if (isFinished) {
@@ -139,7 +139,8 @@ void ProgrammaticScrollAnimator::updateCompositorAnimations()
 
         if (!sentToCompositor) {
             m_runState = RunState::RunningOnMainThread;
-            m_animationCurve->setInitialValue(FloatPoint(m_scrollableArea->scrollPosition()));
+            m_animationCurve->setInitialValue(compositorOffsetFromBlinkOffset(
+                FloatPoint(m_scrollableArea->scrollPosition())));
             if (!m_scrollableArea->scheduleAnimation()) {
                 notifyPositionChanged(IntPoint(m_targetOffset.x(), m_targetOffset.y()));
                 resetAnimationState();
@@ -158,7 +159,8 @@ void ProgrammaticScrollAnimator::layerForCompositedScrollingDidChange(Compositor
         m_runState = RunState::RunningOnMainThread;
         m_compositorAnimationId = 0;
         m_compositorAnimationGroupId = 0;
-        m_animationCurve->setInitialValue(FloatPoint(m_scrollableArea->scrollPosition()));
+        m_animationCurve->setInitialValue(compositorOffsetFromBlinkOffset(
+            FloatPoint(m_scrollableArea->scrollPosition())));
         m_scrollableArea->registerForAnimation();
         if (!m_scrollableArea->scheduleAnimation()) {
             resetAnimationState();