Simplify SVGImage::ResetAnimation

Now that SVGSVGElement::setCurrentTime(...) (or more specifically
SMILTimeContainer::SetElapsed) no longer trigger further updates when
the time container is paused, we can remove the "pending timeline
rewind" workaround.
When doing this also take the opportunity to fold CanScheduleFrame(...)
in SMILTimeContainer into its only caller and simplify a little bit.

Bug: 998526
Change-Id: I9ff3de1e8c4b28284bbf3ed27d128206ea7ee857
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1976410Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#726808}

third_party/blink/renderer/core/svg/animation/smil_time_container.cc

@@ -397,16 +397,6 @@ void SMILTimeContainer::ServiceAnimations() {
   UpdateAnimationsAndScheduleFrameIfNeeded(Elapsed());
 }
 
-bool SMILTimeContainer::CanScheduleFrame(SMILTime earliest_fire_time) const {
-  // If there's synchronization pending (most likely due to syncbases), then
-  // let that complete first before attempting to schedule a frame.
-  if (HasPendingSynchronization())
-    return false;
-  if (!IsTimelineRunning())
-    return false;
-  return earliest_fire_time.IsFinite();
-}
-
 void SMILTimeContainer::UpdateAnimationsAndScheduleFrameIfNeeded(
     SMILTime elapsed) {
   DCHECK(GetDocument().IsActive());
@@ -414,11 +404,13 @@ void SMILTimeContainer::UpdateAnimationsAndScheduleFrameIfNeeded(
 
   UpdateAnimationTimings(elapsed);
   ApplyTimedEffects(elapsed);
-
-  SMILTime next_progress_time = NextProgressTime(elapsed);
   DCHECK(!wakeup_timer_.IsActive());
+  DCHECK(!HasPendingSynchronization());
 
-  if (!CanScheduleFrame(next_progress_time))
+  if (!IsTimelineRunning())
+    return;
+  SMILTime next_progress_time = NextProgressTime(elapsed);
+  if (!next_progress_time.IsFinite())
     return;
   SMILTime delay_time = next_progress_time - elapsed;
   DCHECK(delay_time.IsFinite());

third_party/blink/renderer/core/svg/animation/smil_time_container.h

@@ -106,7 +106,6 @@ class SMILTimeContainer final : public GarbageCollected<SMILTimeContainer> {
   void AnimationPolicyTimerFired(TimerBase*);
   ImageAnimationPolicy AnimationPolicy() const;
   bool HandleAnimationPolicy(AnimationPolicyOnceAction);
-  bool CanScheduleFrame(SMILTime earliest_fire_time) const;
   void UpdateAnimationsAndScheduleFrameIfNeeded(SMILTime elapsed);
   void ResetIntervals();
   void UpdateIntervals(SMILTime presentation_time);

third_party/blink/renderer/core/svg/graphics/svg_image.cc

@@ -99,8 +99,7 @@ class SVGImage::SVGImageLocalFrameClient : public EmptyLocalFrameClient {
 
 SVGImage::SVGImage(ImageObserver* observer, bool is_multipart)
     : Image(observer, is_multipart),
-      paint_controller_(std::make_unique<PaintController>()),
-      has_pending_timeline_rewind_(false) {}
+      paint_controller_(std::make_unique<PaintController>()) {}
 
 SVGImage::~SVGImage() {
   if (frame_client_)
@@ -516,13 +515,6 @@ sk_sp<PaintRecord> SVGImage::PaintRecordForCurrentFrame(const KURL& url) {
   // there may have been a previous url/fragment that needs to be reset.
   view->ProcessUrlFragment(url, /*same_document_navigation=*/false);
 
-  // If the image was reset, we need to rewind the timeline back to 0. This
-  // needs to be done before painting, or else we wouldn't get the correct
-  // reset semantics (we'd paint the "last" frame rather than the one at
-  // time=0.) The reason we do this here and not in resetAnimation() is to
-  // avoid setting timers from the latter.
-  FlushPendingTimelineRewind();
-
   if (RuntimeEnabledFeatures::CompositeAfterPaintEnabled()) {
     view->UpdateAllLifecyclePhases(
         DocumentLifecycle::LifecycleUpdateReason::kOther);
@@ -565,18 +557,6 @@ void SVGImage::DrawInternal(cc::PaintCanvas* canvas,
   StartAnimation();
 }
 
-void SVGImage::ScheduleTimelineRewind() {
-  has_pending_timeline_rewind_ = true;
-}
-
-void SVGImage::FlushPendingTimelineRewind() {
-  if (!has_pending_timeline_rewind_)
-    return;
-  if (SVGSVGElement* root_element = SvgRootElement(page_.Get()))
-    root_element->setCurrentTime(0);
-  has_pending_timeline_rewind_ = false;
-}
-
 void SVGImage::StartAnimation() {
   SVGSVGElement* root_element = SvgRootElement(page_.Get());
   if (!root_element)
@@ -600,7 +580,7 @@ void SVGImage::ResetAnimation() {
     return;
   chrome_client_->SuspendAnimation();
   root_element->pauseAnimations();
-  ScheduleTimelineRewind();
+  root_element->setCurrentTime(0);
 }
 
 void SVGImage::RestoreAnimation() {

third_party/blink/renderer/core/svg/graphics/svg_image.h

@@ -210,8 +210,6 @@ class CORE_EXPORT SVGImage final : public Image {
                            const KURL&);
 
   void StopAnimation();
-  void ScheduleTimelineRewind();
-  void FlushPendingTimelineRewind();
 
   Page* GetPageForTesting() { return page_; }
   void LoadCompleted();
@@ -227,9 +225,8 @@ class CORE_EXPORT SVGImage final : public Image {
   // object size, which in turn depends on the container. One SVGImage may
   // belong to multiple containers so the final image size can't be known in
   // SVGImage. SVGImageForContainer carries the final image size, also called
-  // the "concrete object size". For more, see: SVGImageForContainer.h
+  // the "concrete object size". For more, see svg_image_for_container.h.
   LayoutSize intrinsic_size_;
-  bool has_pending_timeline_rewind_;
 
   enum LoadState {
     kDataChangedNotStarted,