[CRD iOS] Injecting scroll events w/ fling animation

remoting/client/ui/fling_animation.cc

 // Copyright 2017 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 "remoting/client/ui/fling_animation.h"
 
 #include "base/time/default_tick_clock.h"
 
 namespace remoting {
 
 FlingAnimation::FlingAnimation(float time_constant,
                                const FlingCallback& fling_callback)
     : fling_tracker_(time_constant),
       fling_callback_(fling_callback),
       clock_(new base::DefaultTickClock()) {}
 
 FlingAnimation::~FlingAnimation() {}
 
 void FlingAnimation::SetVelocity(float velocity_x, float velocity_y) {
   fling_tracker_.StartFling(velocity_x, velocity_y);
   fling_start_time_ = clock_->NowTicks();
 }
 
 bool FlingAnimation::IsAnimationInProgress() const {
   return fling_tracker_.IsFlingInProgress();
 }
 
 void FlingAnimation::Tick() {
+  if (!IsAnimationInProgress()) {
+    return;
+  }
+
   float dx, dy;
   bool in_progress = fling_tracker_.TrackMovement(
       clock_->NowTicks() - fling_start_time_, &dx, &dy);
   if (in_progress) {
     fling_callback_.Run(dx, dy);
   }
 }
 
 void FlingAnimation::Abort() {
   fling_tracker_.StopFling();
 }
 
 void FlingAnimation::SetTickClockForTest(
     std::unique_ptr<base::TickClock> clock) {
   clock_ = std::move(clock);
 }
 
 }  // namespace remoting