Add SMILInterval::Unresolved() helper

Use this when discarding or otherwise initializing an interval to an
unresolved state - which hopefully slightly more readable than what is
currently used.

Drop some friend declarations from SMILTime that are no longer needed,
while we're in the vicinity.

Bug: 998526
Change-Id: I08531a906c0e093f2786c4c1a925ebd823f99ca4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1856163
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705399}

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

@@ -130,9 +130,6 @@ class SMILTime {
   bool operator<=(SMILTime other) const { return time_ <= other.time_; }
 
  private:
-  friend bool operator!=(const SMILInterval& a, const SMILInterval& b);
-  friend struct SMILTimeHash;
-
   constexpr SMILTime(base::TimeDelta time) : time_(time) {}
 
   base::TimeDelta time_;
@@ -177,10 +174,13 @@ inline bool operator<(const SMILTimeWithOrigin& a,
 // (https://www.w3.org/TR/SMIL3/smil-timing.html#q101)
 struct SMILInterval {
   DISALLOW_NEW();
-  SMILInterval() = default;
-  SMILInterval(const SMILTime& begin, const SMILTime& end)
+  constexpr SMILInterval(const SMILTime& begin, const SMILTime& end)
       : begin(begin), end(end) {}
 
+  static constexpr SMILInterval Unresolved() {
+    return {SMILTime::Unresolved(), SMILTime::Unresolved()};
+  }
+
   bool IsResolved() const { return begin.IsFinite(); }
   bool BeginsAfter(SMILTime time) const { return time < begin; }
   bool BeginsBefore(SMILTime time) const { return !BeginsAfter(time); }

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

@@ -186,8 +186,8 @@ SVGSMILElement::SVGSMILElement(const QualifiedName& tag_name, Document& doc)
       has_end_event_conditions_(false),
       is_waiting_for_first_interval_(true),
       is_scheduled_(false),
-      interval_{SMILTime::Unresolved(), SMILTime::Unresolved()},
-      previous_interval_{SMILTime::Unresolved(), SMILTime::Unresolved()},
+      interval_(SMILInterval::Unresolved()),
+      previous_interval_(SMILInterval::Unresolved()),
       next_interval_time_(SMILTime::Earliest()),
       active_state_(kInactive),
       restart_(kRestartAlways),
@@ -255,8 +255,8 @@ static inline void RemoveInstanceTimesWithOrigin(
 void SVGSMILElement::Reset() {
   active_state_ = kInactive;
   is_waiting_for_first_interval_ = true;
-  interval_ = {SMILTime::Unresolved(), SMILTime::Unresolved()};
-  previous_interval_ = {SMILTime::Unresolved(), SMILTime::Unresolved()};
+  interval_ = SMILInterval::Unresolved();
+  previous_interval_ = SMILInterval::Unresolved();
   next_interval_time_ = SMILTime::Earliest();
   last_progress_ = {0.0f, 0};
 }
@@ -809,7 +809,7 @@ SMILInterval SVGSMILElement::ResolveInterval(SMILTime begin_after,
 
     begin_after = temp_end;
   }
-  return SMILInterval(SMILTime::Unresolved(), SMILTime::Unresolved());
+  return SMILInterval::Unresolved();
 }
 
 void SVGSMILElement::SetNewInterval(const SMILInterval& interval,
@@ -875,7 +875,7 @@ void SVGSMILElement::DiscardOrRevalidateCurrentInterval(
     return;
   // If the current interval has not yet started, discard it and re-resolve.
   if (interval_.BeginsAfter(presentation_time)) {
-    interval_ = {SMILTime::Unresolved(), SMILTime::Unresolved()};
+    interval_ = SMILInterval::Unresolved();
     return;
   }
 
@@ -886,7 +886,7 @@ void SVGSMILElement::DiscardOrRevalidateCurrentInterval(
     if (new_end.IsUnresolved()) {
       // If we have no pending end conditions, discard the current interval.
       if (!end_times_.IsEmpty() && !has_end_event_conditions_) {
-        interval_ = {SMILTime::Unresolved(), SMILTime::Unresolved()};
+        interval_ = SMILInterval::Unresolved();
         return;
       }
     }