Support compositing for active animations in SPv2.

third_party/WebKit/Source/core/animation/CompositorAnimations.cpp

Index: third_party/WebKit/Source/core/animation/CompositorAnimations.cpp
diff --git a/third_party/WebKit/Source/core/animation/CompositorAnimations.cpp b/third_party/WebKit/Source/core/animation/CompositorAnimations.cpp
index c3891274cc5c3929b931a1084d8e14f5547c79d6..61d0947bff02ed7bd3ab73f70681ebc8ed13f1d4 100644
--- a/third_party/WebKit/Source/core/animation/CompositorAnimations.cpp
+++ b/third_party/WebKit/Source/core/animation/CompositorAnimations.cpp
@@ -42,6 +42,7 @@
 #include "core/layout/LayoutObject.h"
 #include "core/layout/compositing/CompositedLayerMapping.h"
 #include "core/paint/FilterEffectBuilder.h"
+#include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/animation/AnimationTranslationUtil.h"
 #include "platform/animation/CompositorAnimation.h"
@@ -344,6 +345,14 @@ bool CompositorAnimations::canStartAnimationOnCompositor(
     const Element& element) {
   if (!Platform::current()->isThreadedAnimationEnabled())
     return false;
+
+  if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+    // TODO(wkorman): Consider effect node for opacity.

[wkorman, 2016/12/15 23:06:00]

Are you adding direct compositing reasons to effect node, or should I do it?

[chrishtr, 2016/12/16 00:31:06]

You can add it. Follow the lead of the other patch and mimic the reasons
computed in CompositingReasonsFinder.

[wkorman, 2016/12/16 23:08:00]

Will do in subsequent change.

+    const TransformPaintPropertyNode* transformNode =
+        element.layoutObject()->paintProperties()->transform();
+    return transformNode && transformNode->hasDirectCompositingReasons();
+  }
+
   return element.layoutObject() &&
          element.layoutObject()->compositingState() == PaintsIntoOwnBacking;
 }