Pass times to SVGSMILElement::ResolveInterval rather than first/next

This gets rid of the IntervalSelector argument, replacing it with a time
which the interval should start after (or at) and end after. With this,
ResolveInterval(...) becomes independent of the current interval
(previously only used as the internal "begin after").
Fold ResolveNextInterval() into its only user.

Bug: 998526
Change-Id: I807327986d5aa7286395ac29019a63d6c8921202
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1825417Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#699872}

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

@@ -816,12 +816,10 @@ SMILTime SVGSMILElement::ResolveActiveEnd(SMILTime resolved_begin,
          std::min(max_value, std::max(min_value, preliminary_active_duration));
 }
 
-SMILInterval SVGSMILElement::ResolveInterval(
-    IntervalSelector interval_selector) const {
-  bool first = interval_selector == kFirstInterval;
+SMILInterval SVGSMILElement::ResolveInterval(SMILTime begin_after,
+                                             SMILTime end_after) const {
   // Simplified version of the pseudocode in
   // http://www.w3.org/TR/SMIL3/smil-timing.html#q90.
-  SMILTime begin_after = first ? SMILTime::Earliest() : interval_.end;
   while (true) {
     SMILTime temp_begin = FindInstanceTime(kBegin, begin_after, true);
     if (temp_begin.IsUnresolved())
@@ -835,9 +833,10 @@ SMILInterval SVGSMILElement::ResolveInterval(
     temp_end = ResolveActiveEnd(temp_begin, temp_end);
     // If this is the first interval being resolved, don't allow it to end
     // before the origin of the timeline.
-    // TODO(fs): Don't resolve intervals that end "in the past".
-    if (!first || temp_end > SMILTime())
+    if (temp_end > end_after) {
+      DCHECK(!temp_begin.IsIndefinite());
       return SMILInterval(temp_begin, temp_end);
+    }
 
     begin_after = temp_end;
   }
@@ -845,8 +844,8 @@ SMILInterval SVGSMILElement::ResolveInterval(
 }
 
 bool SVGSMILElement::ResolveFirstInterval() {
-  SMILInterval first_interval = ResolveInterval(kFirstInterval);
-  DCHECK(!first_interval.begin.IsIndefinite());
+  SMILInterval first_interval =
+      ResolveInterval(SMILTime::Earliest(), SMILTime());
   if (!first_interval.IsResolved() || first_interval == interval_)
     return false;
   interval_ = first_interval;
@@ -854,18 +853,6 @@ bool SVGSMILElement::ResolveFirstInterval() {
   return true;
 }
 
-base::Optional<SMILInterval> SVGSMILElement::ResolveNextInterval() {
-  SMILInterval next_interval = ResolveInterval(kNextInterval);
-  DCHECK(!next_interval.begin.IsIndefinite());
-
-  if (!next_interval.begin.IsUnresolved() &&
-      next_interval.begin != interval_.begin) {
-    return next_interval;
-  }
-
-  return base::nullopt;
-}
-
 SMILTime SVGSMILElement::NextInterestingTime(SMILTime presentation_time) const {
   DCHECK_GE(presentation_time, SMILTime());
   SMILTime next_interesting_interval_time = SMILTime::Indefinite();
@@ -904,8 +891,7 @@ void SVGSMILElement::BeginListChanged(SMILTime event_time) {
     return;
   // Begin time changed, re-resolve the interval.
   SMILTime old_begin = interval_.begin;
-  interval_.end = event_time;
-  interval_ = ResolveInterval(kNextInterval);
+  interval_ = ResolveInterval(event_time, event_time);
   DCHECK(interval_.IsResolved());
   if (interval_.begin != old_begin) {
     if (GetActiveState() == kActive && interval_.BeginsAfter(event_time)) {
@@ -955,7 +941,9 @@ void SVGSMILElement::CheckAndUpdateInterval(SMILTime elapsed) {
 
   if ((new_interval && new_interval->EndsBefore(elapsed)) ||
       (!new_interval && interval_.EndsBefore(elapsed))) {
-    new_interval = ResolveNextInterval();
+    SMILInterval next_interval = ResolveInterval(interval_.end, elapsed);
+    if (next_interval.IsResolved() && next_interval.begin != interval_.begin)
+      new_interval = next_interval;
   }
 
   if (new_interval) {

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

@@ -176,11 +176,8 @@ class CORE_EXPORT SVGSMILElement : public SVGElement, public SVGTests {
                             SMILTime minimum_time,
                             bool equals_minimum_ok) const;
 
-  enum IntervalSelector { kFirstInterval, kNextInterval };
-
-  SMILInterval ResolveInterval(IntervalSelector) const;
+  SMILInterval ResolveInterval(SMILTime begin_after, SMILTime end_after) const;
   bool ResolveFirstInterval();
-  base::Optional<SMILInterval> ResolveNextInterval();
   SMILTime ResolveActiveEnd(SMILTime resolved_begin,
                             SMILTime resolved_end) const;
   SMILTime RepeatingDuration() const;