Add SVGSMILElement::BeginTimeForPrioritization

Add this method, removing the two old IsFrozen() and
PreviousIntervalBegin() to reduce API surface.

Bug: 998526
Change-Id: I688dffc96cfe05462b81dbb3cbefad0d38ea00e1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1795826
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695574}

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

@@ -39,13 +39,8 @@ struct PriorityCompare {
                   const Member<SVGSMILElement>& b) {
     // FIXME: This should also consider possible timing relations between the
     // elements.
-    SMILTime a_begin = a->IntervalBegin();
-    SMILTime b_begin = b->IntervalBegin();
-    // Frozen elements need to be prioritized based on their previous interval.
-    a_begin = a->IsFrozen() && elapsed_ < a_begin ? a->PreviousIntervalBegin()
-                                                  : a_begin;
-    b_begin = b->IsFrozen() && elapsed_ < b_begin ? b->PreviousIntervalBegin()
-                                                  : b_begin;
+    SMILTime a_begin = a->BeginTimeForPrioritization(elapsed_);
+    SMILTime b_begin = b->BeginTimeForPrioritization(elapsed_);
     if (a_begin == b_begin)
       return a->DocumentOrderIndex() < b->DocumentOrderIndex();
     return a_begin < b_begin;

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

@@ -617,8 +617,13 @@ SMILTime SVGSMILElement::Elapsed() const {
   return time_container_ ? time_container_->Elapsed() : 0;
 }
 
-bool SVGSMILElement::IsFrozen() const {
-  return GetActiveState() == kFrozen;
+SMILTime SVGSMILElement::BeginTimeForPrioritization(
+    double presentation_time) const {
+  if (GetActiveState() == kFrozen) {
+    if (interval_.BeginsAfter(presentation_time))
+      return previous_interval_.begin;
+  }
+  return interval_.begin;
 }
 
 SMILTime SVGSMILElement::Dur() const {

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

@@ -81,7 +81,7 @@ class CORE_EXPORT SVGSMILElement : public SVGElement, public SVGTests {
   SMILTime Elapsed() const;
 
   SMILTime IntervalBegin() const { return interval_.begin; }
-  SMILTime PreviousIntervalBegin() const { return previous_interval_.begin; }
+  SMILTime BeginTimeForPrioritization(double presentation_time) const;
   SMILTime SimpleDuration() const;
 
   bool NeedsToProgress(double elapsed);
@@ -104,7 +104,6 @@ class CORE_EXPORT SVGSMILElement : public SVGElement, public SVGTests {
   static SMILTime ParseOffsetValue(const String&);
 
   bool IsContributing(double elapsed) const;
-  bool IsFrozen() const;
 
   unsigned DocumentOrderIndex() const { return document_order_index_; }
   void SetDocumentOrderIndex(unsigned index) { document_order_index_ = index; }