TransitionEvent: store elapsed time in an AnimationTimeDelta

As part of the rewriting of Blink Animation Engine we're replacing the way the
elapsed time is represented inside a TransitionEvent. The spec mentions it must
be a double but we can use AnimationTimeDelta as the internal representation.
This change reduces a little bit the number of required conversions between
AnimationTimeDelta and double.

Bug: 737867
Change-Id: Ide96f3906c3937c6d4af893a9677211c7f8de8f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1907247Reviewed-by: Kevin Ellis <kevers@chromium.org>
Commit-Queue: Sergio Villar <svillar@igalia.com>
Cr-Commit-Position: refs/heads/master@{#714261}

third_party/blink/renderer/core/animation/css/css_animations.cc

@@ -218,8 +218,8 @@ std::unique_ptr<TypedInterpolationValue> SampleAnimation(
 
 // Returns the start time of an animation given the start delay. A negative
 // start delay results in the animation starting with non-zero progress.
-double StartTimeFromDelay(double start_delay) {
-  return start_delay < 0 ? -start_delay : 0;
+AnimationTimeDelta StartTimeFromDelay(double start_delay) {
+  return AnimationTimeDelta::FromSecondsD(start_delay < 0 ? -start_delay : 0);
 }
 
 }  // namespace
@@ -1201,9 +1201,9 @@ void CSSAnimations::TransitionEventDelegate::OnEventCondition(
                previous_phase_ == Timing::kPhaseAfter) {
       // If the transition is progressing backwards it is considered to have
       // started at the end position.
-      EnqueueEvent(
-          event_type_names::kTransitionstart,
-          animation_node.SpecifiedTiming().iteration_duration->InSecondsF());
+      DCHECK(animation_node.SpecifiedTiming().iteration_duration.has_value());
+      EnqueueEvent(event_type_names::kTransitionstart,
+                   animation_node.SpecifiedTiming().iteration_duration.value());
     }
   }
 
@@ -1212,9 +1212,9 @@ void CSSAnimations::TransitionEventDelegate::OnEventCondition(
         (previous_phase_ == Timing::kPhaseActive ||
          previous_phase_ == Timing::kPhaseBefore ||
          previous_phase_ == Timing::kPhaseNone)) {
-      EnqueueEvent(
-          event_type_names::kTransitionend,
-          animation_node.SpecifiedTiming().iteration_duration->InSecondsF());
+      DCHECK(animation_node.SpecifiedTiming().iteration_duration.has_value());
+      EnqueueEvent(event_type_names::kTransitionend,
+                   animation_node.SpecifiedTiming().iteration_duration.value());
     } else if (current_phase == Timing::kPhaseBefore &&
                (previous_phase_ == Timing::kPhaseActive ||
                 previous_phase_ == Timing::kPhaseAfter)) {
@@ -1242,7 +1242,7 @@ void CSSAnimations::TransitionEventDelegate::OnEventCondition(
       // current_phase != previous_phase_ (see early return at the beginning).
       DCHECK(cancel_active_time);
       EnqueueEvent(event_type_names::kTransitioncancel,
-                   cancel_active_time->InSecondsF());
+                   cancel_active_time.value());
     }
   }
 
@@ -1251,7 +1251,7 @@ void CSSAnimations::TransitionEventDelegate::OnEventCondition(
 
 void CSSAnimations::TransitionEventDelegate::EnqueueEvent(
     const WTF::AtomicString& type,
-    double elapsed_time) {
+    const AnimationTimeDelta& elapsed_time) {
   String property_name =
       property_.IsCSSCustomProperty()
           ? property_.CustomPropertyName()

third_party/blink/renderer/core/animation/css/css_animations.h

@@ -234,7 +234,8 @@ class CORE_EXPORT CSSAnimations final {
     void Trace(blink::Visitor*) override;
 
    private:
-    void EnqueueEvent(const WTF::AtomicString& type, double elapsed_time);
+    void EnqueueEvent(const WTF::AtomicString& type,
+                      const AnimationTimeDelta& elapsed_time);
 
     const Element& TransitionTarget() const { return *transition_target_; }
     EventTarget* GetEventTarget() const;

third_party/blink/renderer/core/events/transition_event.cc

@@ -30,11 +30,11 @@
 
 namespace blink {
 
-TransitionEvent::TransitionEvent() : elapsed_time_(0) {}
+TransitionEvent::TransitionEvent() = default;
 
 TransitionEvent::TransitionEvent(const AtomicString& type,
                                  const String& property_name,
-                                 double elapsed_time,
+                                 const AnimationTimeDelta& elapsed_time,
                                  const String& pseudo_element)
     : Event(type, Bubbles::kYes, Cancelable::kYes),
       property_name_(property_name),
@@ -43,11 +43,13 @@ TransitionEvent::TransitionEvent(const AtomicString& type,
 
 TransitionEvent::TransitionEvent(const AtomicString& type,
                                  const TransitionEventInit* initializer)
-    : Event(type, initializer), elapsed_time_(0) {
+    : Event(type, initializer) {
   if (initializer->hasPropertyName())
     property_name_ = initializer->propertyName();
-  if (initializer->hasElapsedTime())
-    elapsed_time_ = initializer->elapsedTime();
+  if (initializer->hasElapsedTime()) {
+    elapsed_time_ =
+        AnimationTimeDelta::FromSecondsD(initializer->elapsedTime());
+  }
   if (initializer->hasPseudoElement())
     pseudo_element_ = initializer->pseudoElement();
 }
@@ -59,7 +61,7 @@ const String& TransitionEvent::propertyName() const {
 }
 
 double TransitionEvent::elapsedTime() const {
-  return elapsed_time_;
+  return elapsed_time_.InSecondsF();
 }
 
 const String& TransitionEvent::pseudoElement() const {

third_party/blink/renderer/core/events/transition_event.h

@@ -27,6 +27,7 @@
 #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_EVENTS_TRANSITION_EVENT_H_
 #define THIRD_PARTY_BLINK_RENDERER_CORE_EVENTS_TRANSITION_EVENT_H_
 
+#include "third_party/blink/renderer/core/animation/animation_time_delta.h"
 #include "third_party/blink/renderer/core/dom/events/event.h"
 #include "third_party/blink/renderer/core/events/transition_event_init.h"
 
@@ -41,7 +42,7 @@ class TransitionEvent final : public Event {
   }
   static TransitionEvent* Create(const AtomicString& type,
                                  const String& property_name,
-                                 double elapsed_time,
+                                 const AnimationTimeDelta& elapsed_time,
                                  const String& pseudo_element) {
     return MakeGarbageCollected<TransitionEvent>(type, property_name,
                                                  elapsed_time, pseudo_element);
@@ -54,7 +55,7 @@ class TransitionEvent final : public Event {
   TransitionEvent();
   TransitionEvent(const AtomicString& type,
                   const String& property_name,
-                  double elapsed_time,
+                  const AnimationTimeDelta& elapsed_time,
                   const String& pseudo_element);
   TransitionEvent(const AtomicString& type,
                   const TransitionEventInit* initializer);
@@ -70,7 +71,7 @@ class TransitionEvent final : public Event {
 
  private:
   String property_name_;
-  double elapsed_time_;
+  AnimationTimeDelta elapsed_time_;
   String pseudo_element_;
 };