Support per property CSS Animation stacks

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 d6b55eccc798768cb4eb0664a90a322f9c3fbca4..b4b8705976f810ab9ad16b3c1f3921ac4f69944d 100644
--- a/Source/core/animation/AnimationStack.cpp
+++ b/Source/core/animation/AnimationStack.cpp
@@ -32,8 +32,9 @@
 #include "core/animation/AnimationStack.h"
 
 #include "core/animation/CompositorAnimations.h"
-#include "core/animation/StyleInterpolation.h"
+#include "core/animation/InvalidatableStyleInterpolation.h"
 #include "core/animation/css/CSSAnimations.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/BitArray.h"
 #include "wtf/NonCopyingSort.h"
 #include <algorithm>
@@ -42,10 +43,20 @@ namespace blink {
 
 namespace {
 
-void copyToActiveInterpolationMap(const Vector<RefPtr<Interpolation>>& source, ActiveInterpolationMap& target)
+void copyToActiveInterpolationMap(const Vector<RefPtr<Interpolation>>& source, ActiveInterpolationsMap& target)

[dstockwell, 2015/09/07 03:11:36]

copyToActiveInterpolation*s*Map?

[alancutter (OOO until 2018), 2015/09/07 03:36:46]

Done.

 {
     for (const auto& interpolation : source) {
-        target.set(interpolation->property(), interpolation.get());
+        ActiveInterpolationsMap::iterator entry = target.find(interpolation->property());
+        if (entry == target.end()) {
+            // Python version of this line: target[interpolation.property] = [interpolation]
+            target.set(interpolation->property(), ActiveInterpolations(1)).storedValue->value.at(0) = interpolation.get();

[dstockwell, 2015/09/07 03:11:36]

is there a way to avoid the second hash here?

[alancutter (OOO until 2018), 2015/09/07 03:36:46]

Done.

+        } else if (RuntimeEnabledFeatures::stackedCSSPropertyAnimationsEnabled()
+            && interpolation->isInvalidatableStyleInterpolation()
+            && toInvalidatableStyleInterpolation(*interpolation).dependsOnUnderlyingValue()) {

[dstockwell, 2015/09/07 03:11:36]

Why is dependonunderlying part of invalidatablestyleinterpolation -- I assume
this will apply to other interpolations too?

[alancutter (OOO until 2018), 2015/09/07 03:36:46]

Correct, InvalidatableStyleInterpolation will eventually be merged upstream into
Interpolation once the old code has been replaced completely.

+            entry->value.append(interpolation.get());
+        } else {
+            entry->value.at(0) = interpolation.get();
+        }
     }
 }
 
@@ -55,7 +66,7 @@ bool compareEffects(const Member<SampledEffect>& effect1, const Member<SampledEf
     return effect1->sequenceNumber() < effect2->sequenceNumber();
 }
 
-void copyNewAnimationsToActiveInterpolationMap(const HeapVector<Member<InertEffect>>& newAnimations, ActiveInterpolationMap& result)
+void copyNewAnimationsToActiveInterpolationMap(const HeapVector<Member<InertEffect>>& newAnimations, ActiveInterpolationsMap& result)
 {
     for (const auto& newAnimation : newAnimations) {
         OwnPtr<Vector<RefPtr<Interpolation>>> sample;
@@ -81,11 +92,11 @@ bool AnimationStack::hasActiveAnimationsOnCompositor(CSSPropertyID property) con
     return false;
 }
 
-ActiveInterpolationMap AnimationStack::activeInterpolations(AnimationStack* animationStack, const HeapVector<Member<InertEffect>>* newAnimations, const HeapHashSet<Member<const Animation>>* suppressedAnimations, KeyframeEffect::Priority priority, double timelineCurrentTime)
+ActiveInterpolationsMap AnimationStack::activeInterpolations(AnimationStack* animationStack, const HeapVector<Member<InertEffect>>* newAnimations, const HeapHashSet<Member<const Animation>>* suppressedAnimations, KeyframeEffect::Priority priority, double timelineCurrentTime)
 {
     // We don't exactly know when new animations will start, but timelineCurrentTime is a good estimate.
 
-    ActiveInterpolationMap result;
+    ActiveInterpolationsMap result;
 
     if (animationStack) {
         HeapVector<Member<SampledEffect>>& effects = animationStack->m_effects;