Avoid useless initialization in ScrollAnimatorNone::PerAxisData::animateScroll()

Source/platform/scroll/ScrollAnimatorNone.cpp

 /*
  * Copyright (c) 2011, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 306 matching lines @@
         m_attackPosition = m_releasePosition - (m_animationTime - m_releaseTime - m_attackTime) * m_desiredVelocity;
 
     if (sustainTimeLeft) {
         double roundOff = m_releasePosition - ((attackAreaLeft ? m_attackPosition : *m_currentPosition) + m_desiredVelocity * sustainTimeLeft);
         m_desiredVelocity += roundOff / sustainTimeLeft;
     }
 
     return true;
 }
 
+inline double ScrollAnimatorNone::PerAxisData::newScrollAnimationPosition(double deltaTime)
+{
+    if (deltaTime < m_attackTime)
+        return attackCurve(m_attackCurve, deltaTime, m_attackTime, m_startPosition, m_attackPosition);
+    if (deltaTime < (m_animationTime - m_releaseTime))
+        return m_attackPosition + (deltaTime - m_attackTime) * m_desiredVelocity;
+    // release is based on targeting the exact final position.
+    double releaseDeltaT = deltaTime - (m_animationTime - m_releaseTime);
+    return releaseCurve(m_releaseCurve, releaseDeltaT, m_releaseTime, m_releasePosition, m_desiredPosition);
+}
+
 // FIXME: Add in jank detection trace events into this function.
 bool ScrollAnimatorNone::PerAxisData::animateScroll(double currentTime)
 {
     double lastScrollInterval = currentTime - m_lastAnimationTime;
     if (lastScrollInterval < kMinimumTimerInterval)
         return true;
 
     m_lastAnimationTime = currentTime;
 
     double deltaTime = currentTime - m_startTime;
-    double newPosition = *m_currentPosition;
 
     if (deltaTime > m_animationTime) {
         *m_currentPosition = m_desiredPosition;
         reset();
         return false;
     }
-    if (deltaTime < m_attackTime)
-        newPosition = attackCurve(m_attackCurve, deltaTime, m_attackTime, m_startPosition, m_attackPosition);
-    else if (deltaTime < (m_animationTime - m_releaseTime))
-        newPosition = m_attackPosition + (deltaTime - m_attackTime) * m_desiredVelocity;
-    else {
-        // release is based on targeting the exact final position.
-        double releaseDeltaT = deltaTime - (m_animationTime - m_releaseTime);
-        newPosition = releaseCurve(m_releaseCurve, releaseDeltaT, m_releaseTime, m_releasePosition, m_desiredPosition);
-    }
-
+    double newPosition = newScrollAnimationPosition(deltaTime);
     // Normalize velocity to a per second amount. Could be used to check for jank.
     if (lastScrollInterval > 0)
         m_currentVelocity = (newPosition - *m_currentPosition) / lastScrollInterval;
     *m_currentPosition = newPosition;
 
     return true;
 }
 
 void ScrollAnimatorNone::PerAxisData::updateVisibleLength(int visibleLength)
 {
@@ skipping 153 matching lines @@
     return m_animationActive;
 }
 
 void ScrollAnimatorNone::stopAnimationTimerIfNeeded()
 {
     if (animationTimerActive())
         m_animationActive = false;
 }
 
 } // namespace WebCore