Sink interval notification out of SVGSMILElement::ResolveFirstInterval

In the majority of cases SMILTimeContainer::NotifyIntervalsChanged is
already called - or doesn't need to be called either because we're about
to perform an update already (Reset()), or because there is no time
container to notify anyway (constructor).

Bug: 998526
Change-Id: I2e36cbd622a79f3f74f2edf170e6e1d34be3582c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1810897Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#697630}

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

@@ -190,8 +190,12 @@ struct SMILInterval {
   SMILTime end;
 };
 
+inline bool operator==(const SMILInterval& a, const SMILInterval& b) {
+  return a.begin == b.begin && a.end == b.end;
+}
+
 inline bool operator!=(const SMILInterval& a, const SMILInterval& b) {
-  return a.begin != b.begin || a.end != b.end;
+  return !(a == b);
 }
 
 struct SMILTimeHash {

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

@@ -857,17 +857,14 @@ SMILInterval SVGSMILElement::ResolveInterval(
   return SMILInterval(SMILTime::Unresolved(), SMILTime::Unresolved());
 }
 
-void SVGSMILElement::ResolveFirstInterval() {
+bool SVGSMILElement::ResolveFirstInterval() {
   SMILInterval first_interval = ResolveInterval(kFirstInterval);
   DCHECK(!first_interval.begin.IsIndefinite());
-
-  if (!first_interval.begin.IsUnresolved() && first_interval != interval_) {
-    interval_ = first_interval;
-    NotifyDependentsIntervalChanged(interval_);
-
-    if (time_container_)
-      time_container_->NotifyIntervalsChanged();
-  }
+  if (!first_interval.IsResolved() || first_interval == interval_)
+    return false;
+  interval_ = first_interval;
+  NotifyDependentsIntervalChanged(interval_);
+  return true;
 }
 
 base::Optional<SMILInterval> SVGSMILElement::ResolveNextInterval() {
@@ -1113,7 +1110,8 @@ bool SVGSMILElement::NeedsToProgress(SMILTime elapsed) {
 
   if (is_waiting_for_first_interval_) {
     is_waiting_for_first_interval_ = false;
-    ResolveFirstInterval();
+    if (ResolveFirstInterval())
+      time_container_->NotifyIntervalsChanged();
   }
   return true;
 }

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

@@ -185,7 +185,7 @@ class CORE_EXPORT SVGSMILElement : public SVGElement, public SVGTests {
   enum IntervalSelector { kFirstInterval, kNextInterval };
 
   SMILInterval ResolveInterval(IntervalSelector) const;
-  void ResolveFirstInterval();
+  bool ResolveFirstInterval();
   base::Optional<SMILInterval> ResolveNextInterval();
   SMILTime ResolveActiveEnd(SMILTime resolved_begin,
                             SMILTime resolved_end) const;