Backed out changeset 25a4a1aecec4 (bug 1131749) for gtest failures.

CLOSED TREE

gfx/layers/apz/src/Axis.cpp

@@ -263,23 +263,6 @@ void Axis::StepOverscrollAnimation(double aStepDurationMilliseconds) {
   // Adjust the amount of overscroll based on the velocity.
   // Note that we allow for oscillations.
   mOverscroll += (mVelocity * aStepDurationMilliseconds);
-
-  // Our mechanism for translating a set of mOverscroll values that oscillate
-  // around zero to a set of GetOverscroll() values that have the same sign
-  // (so content is always stretched, never compressed) assumes that
-  // mOverscroll does not exceed mFirstOverscrollAnimationSample in magnitude.
-  // If our calculations were exact, this would be the case, as
-  // mFirstOverscrollAnimationSample is the value of mOverscroll at the first
-  // peak of the oscillation, and a dampened spring should never attain a
-  // displacement greater in magnitude than a previous peak. In our
-  // approximation calculations, however, this may not hold exactly. To ensure
-  // the assumption is not violated, we clamp the magnitude of mOverscroll.
-  if (fabs(mOverscroll) > fabs(mFirstOverscrollAnimationSample)) {
-    mOverscroll = (mOverscroll >= 0)
-                ? fabs(mFirstOverscrollAnimationSample)
-                : -fabs(mFirstOverscrollAnimationSample);
-
-  }
 }
 
 bool Axis::SampleOverscrollAnimation(const TimeDuration& aDelta) {