Make scroll animation less "drunk"

Tries to use the new bezier curves to approximate our old smooth
scrolling behavior.

Change-Id: I3b319025fb0339ec95c0a29525f2dde0631866ed
Reviewed-by: Michael Brüning <michael.bruning@theqtcompany.com>

5 files changed, 15 insertions, 6 deletions

diff --git a/chromium/cc/animation/scroll_offset_animation_curve.cc b/chromium/cc/animation/scroll_offset_animation_curve.cc
index dad0ee27e43..b8da2b15c95 100644
--- a/chromium/cc/animation/scroll_offset_animation_curve.cc
+++ b/chromium/cc/animation/scroll_offset_animation_curve.cc
@@ -43,13 +43,13 @@ static float MaximumDimension(const gfx::Vector2dF& delta) {
 static std::unique_ptr<TimingFunction> EaseOutWithInitialVelocity(
     double velocity) {
   // Clamp velocity to a sane value.
-  velocity = std::min(std::max(velocity, -1000.0), 1000.0);
+  velocity = std::min(std::max(velocity, -100.0), 100.0);
 
-  // Based on CubicBezierTimingFunction::EaseType::EASE_IN_OUT preset
+  // Based on CubicBezierTimingFunction::EaseType::EASE_OUT_NATURAL preset
   // with first control point scaled.
-  const double x1 = 0.42;
+  const double x1 = 0.25;
   const double y1 = velocity * x1;
-  return CubicBezierTimingFunction::Create(x1, y1, 0.58, 1);
+  return CubicBezierTimingFunction::Create(x1, y1, 0.45, 0.94);
 }
 
 }  // namespace
diff --git a/chromium/cc/animation/scroll_offset_animations_impl.cc b/chromium/cc/animation/scroll_offset_animations_impl.cc
index 2e1a274e925..e1be4103a19 100644
--- a/chromium/cc/animation/scroll_offset_animations_impl.cc
+++ b/chromium/cc/animation/scroll_offset_animations_impl.cc
@@ -43,7 +43,7 @@ void ScrollOffsetAnimationsImpl::ScrollAnimationCreate(
   std::unique_ptr<ScrollOffsetAnimationCurve> curve =
       ScrollOffsetAnimationCurve::Create(
           target_offset, CubicBezierTimingFunction::CreatePreset(
-                             CubicBezierTimingFunction::EaseType::EASE_IN_OUT),
+                             CubicBezierTimingFunction::EaseType::EASE_OUT_NATURAL),
           ScrollOffsetAnimationCurve::DurationBehavior::INVERSE_DELTA);
   curve->SetInitialValue(current_offset, delayed_by);
   TRACE_EVENT_INSTANT1("cc", "ScrollAnimationCreate", TRACE_EVENT_SCOPE_THREAD,
diff --git a/chromium/cc/animation/timing_function.cc b/chromium/cc/animation/timing_function.cc
index ad73588c6e4..0bf3f966aa7 100644
--- a/chromium/cc/animation/timing_function.cc
+++ b/chromium/cc/animation/timing_function.cc
@@ -33,6 +33,9 @@ CubicBezierTimingFunction::CreatePreset(EaseType ease_type) {
     case EaseType::EASE_IN_OUT:
       return base::WrapUnique(
           new CubicBezierTimingFunction(ease_type, 0.42, 0.0, 0.58, 1));
+    case EaseType::EASE_OUT_NATURAL:
+      return base::WrapUnique(
+          new CubicBezierTimingFunction(ease_type, 0.26, 0.46, 0.45, 0.94));
     default:
       NOTREACHED();
       return nullptr;
diff --git a/chromium/cc/animation/timing_function.h b/chromium/cc/animation/timing_function.h
index 32bbf95fe56..2ac2a35b5d9 100644
--- a/chromium/cc/animation/timing_function.h
+++ b/chromium/cc/animation/timing_function.h
@@ -34,7 +34,7 @@ class CC_ANIMATION_EXPORT TimingFunction {
 
 class CC_ANIMATION_EXPORT CubicBezierTimingFunction : public TimingFunction {
  public:
-  enum class EaseType { EASE, EASE_IN, EASE_OUT, EASE_IN_OUT, CUSTOM };
+  enum class EaseType { EASE, EASE_IN, EASE_OUT, EASE_IN_OUT, EASE_OUT_NATURAL, CUSTOM };
 
   static std::unique_ptr<CubicBezierTimingFunction> CreatePreset(
       EaseType ease_type);
diff --git a/chromium/third_party/blink/renderer/platform/animation/timing_function.cc b/chromium/third_party/blink/renderer/platform/animation/timing_function.cc
index 51a362704e0..a9fa01c7f0c 100644
--- a/chromium/third_party/blink/renderer/platform/animation/timing_function.cc
+++ b/chromium/third_party/blink/renderer/platform/animation/timing_function.cc
@@ -36,6 +36,9 @@ CubicBezierTimingFunction* CubicBezierTimingFunction::Preset(
   DEFINE_STATIC_REF(
       CubicBezierTimingFunction, ease_in_out,
       (base::AdoptRef(new CubicBezierTimingFunction(EaseType::EASE_IN_OUT))));
+  DEFINE_STATIC_REF(
+      CubicBezierTimingFunction, ease_out_natural,
+      (base::AdoptRef(new CubicBezierTimingFunction(EaseType::EASE_OUT_NATURAL))));
 
   switch (ease_type) {
     case EaseType::EASE:
@@ -46,6 +49,8 @@ CubicBezierTimingFunction* CubicBezierTimingFunction::Preset(
       return ease_out;
     case EaseType::EASE_IN_OUT:
       return ease_in_out;
+    case EaseType::EASE_OUT_NATURAL:
+      return ease_out_natural;
     default:
       NOTREACHED();
       return nullptr;
@@ -62,6 +67,7 @@ String CubicBezierTimingFunction::ToString() const {
       return "ease-out";
     case CubicBezierTimingFunction::EaseType::EASE_IN_OUT:
       return "ease-in-out";
+    case CubicBezierTimingFunction::EaseType::EASE_OUT_NATURAL:
     case CubicBezierTimingFunction::EaseType::CUSTOM:
       return "cubic-bezier(" + String::NumberToStringECMAScript(this->X1()) +
              ", " + String::NumberToStringECMAScript(this->Y1()) + ", " +