Web Animations: Sort Animations in the AnimationStack

Source/core/animation/AnimationStack.cpp

Index: Source/core/animation/AnimationStack.cpp
diff --git a/Source/core/animation/AnimationStack.cpp b/Source/core/animation/AnimationStack.cpp
index b1959b31a11f08f86e669c36ef084811a3474cb6..0fc86c0045fbbff57291c0376acba8b978905619 100644
--- a/Source/core/animation/AnimationStack.cpp
+++ b/Source/core/animation/AnimationStack.cpp
@@ -30,8 +30,8 @@
 
 #include "config.h"
 #include "core/animation/AnimationStack.h"
-#include "core/animation/Interpolation.h"
 
+#include "core/animation/Interpolation.h"
 #include "core/animation/css/CSSAnimations.h"
 
 namespace WebCore {
@@ -47,6 +47,22 @@ void copyToActiveInterpolationMap(const WillBeHeapVector<RefPtrWillBeMember<WebC
     }
 }
 
+bool compareAnimations(Animation* animation1, Animation* animation2)
+{
+    ASSERT(animation1->player() && animation2->player());
+    return AnimationPlayer::hasLowerPriority(animation1->player(), animation2->player());
+}
+
+void copyNewAnimationsToActiveInterpolationMap(const Vector<InertAnimation*>& newAnimations, WillBeHeapHashMap<CSSPropertyID, RefPtrWillBeMember<Interpolation> >& result)
+{
+    for (size_t i = 0; i < newAnimations.size(); ++i) {
+        OwnPtrWillBeRawPtr<WillBeHeapVector<RefPtrWillBeMember<Interpolation> > > sample = newAnimations[i]->sample();
+        if (sample) {
+            copyToActiveInterpolationMap(*sample, result);
+        }
+    }
+}
+
 } // namespace
 
 bool AnimationStack::affects(CSSPropertyID property) const
@@ -67,30 +83,31 @@ bool AnimationStack::hasActiveAnimationsOnCompositor(CSSPropertyID property) con
     return false;
 }
 
-WillBeHeapHashMap<CSSPropertyID, RefPtrWillBeMember<Interpolation> > AnimationStack::activeInterpolations(const AnimationStack* animationStack, const Vector<InertAnimation*>* newAnimations, const HashSet<const AnimationPlayer*>* cancelledAnimationPlayers, Animation::Priority priority)
+WillBeHeapHashMap<CSSPropertyID, RefPtrWillBeMember<Interpolation> > AnimationStack::activeInterpolations(AnimationStack* animationStack, const Vector<InertAnimation*>* newAnimations, const HashSet<const AnimationPlayer*>* cancelledAnimationPlayers, Animation::Priority priority, double timelineCurrentTime)
 {
+    // We don't exactly know when new animations will start, but timelineCurrentTime is a good estimate.
+
     WillBeHeapHashMap<CSSPropertyID, RefPtrWillBeMember<Interpolation> > result;
 
     if (animationStack) {
-        const Vector<Animation*>& animations = animationStack->m_activeAnimations;
+        Vector<Animation*>& animations = animationStack->m_activeAnimations;
+        std::sort(animations.begin(), animations.end(), compareAnimations);
         for (size_t i = 0; i < animations.size(); ++i) {
             Animation* animation = animations[i];
             if (animation->priority() != priority)
                 continue;
             if (cancelledAnimationPlayers && cancelledAnimationPlayers->contains(animation->player()))
                 continue;
+            if (animation->player()->startTime() > timelineCurrentTime && newAnimations) {
+                copyNewAnimationsToActiveInterpolationMap(*newAnimations, result);
+                newAnimations = 0;
+            }
             copyToActiveInterpolationMap(animation->activeInterpolations(), result);
         }
     }
 
-    if (newAnimations) {
-        for (size_t i = 0; i < newAnimations->size(); ++i) {
-            OwnPtrWillBeRawPtr<WillBeHeapVector<RefPtrWillBeMember<Interpolation> > > sample = newAnimations->at(i)->sample();
-            if (sample) {
-                copyToActiveInterpolationMap(*sample, result);
-            }
-        }
-    }
+    if (newAnimations)
+        copyNewAnimationsToActiveInterpolationMap(*newAnimations, result);
 
     return result;
 }