Early terminate flings when scrolling impossible

ui/gfx/android/scroller.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/android/scroller.h"
 
 #include <cmath>
 
 #include "base/lazy_instance.h"
 
@@ skipping 258 matching lines @@
   final_y_ = start_y + total_distance * coeff_y;
   final_y_ = Clamped(final_y_, min_y_, max_y_);
 
   RecomputeDeltas();
 }
 
 bool Scroller::ComputeScrollOffset(base::TimeTicks time) {
   if (finished_)
     return false;
 
+  if (time == curr_time_)
+    return true;
+
   base::TimeDelta time_passed = time - start_time_;
 
   if (time_passed < base::TimeDelta()) {
     time_passed = base::TimeDelta();
   }
 
   if (time_passed >= duration_) {
     curr_x_ = final_x_;
     curr_y_ = final_y_;
     curr_time_ = start_time_ + duration_;
@@ skipping 138 matching lines @@
 }
 
 double Scroller::GetSplineFlingDistance(float velocity) const {
   const double l = GetSplineDeceleration(velocity);
   const double decel_minus_one = kDecelerationRate - 1.0;
   return fling_friction_ * tuning_coeff_ *
          std::exp(kDecelerationRate / decel_minus_one * l);
 }
 
 }  // namespace gfx