[SPv2] Decomposite otherwise-compositable animations that paint nothing.

third_party/WebKit/Source/core/animation/CompositorPendingAnimations.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef CompositorPendingAnimations_h
 #define CompositorPendingAnimations_h
 
 #include "core/CoreExport.h"
 #include "core/animation/Animation.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "platform/Timer.h"
+#include "platform/graphics/CompositorElementId.h"
 #include "platform/heap/Handle.h"
+#include "wtf/Optional.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 // Manages the starting of pending animations on the compositor following a
 // compositing update.
 // For CSS Animations, used to synchronize the start of main-thread animations
 // with compositor animations when both classes of CSS Animations are triggered
 // by the same recalc
 class CORE_EXPORT CompositorPendingAnimations final
     : public GarbageCollectedFinalized<CompositorPendingAnimations> {
  public:
   explicit CompositorPendingAnimations(Document& document)
       : m_timer(TaskRunnerHelper::get(TaskType::UnspecedTimer, &document),
                 this,
                 &CompositorPendingAnimations::timerFired),
         m_compositorGroup(1) {}
 
   void add(Animation*);
   // Returns whether we are waiting for an animation to start and should
   // service again on the next frame.
-  bool update(bool startOnCompositor = true);
+  bool update(const Optional<CompositorElementIdSet>&,
+              bool startOnCompositor = true);
   void notifyCompositorAnimationStarted(double monotonicAnimationStartTime,
                                         int compositorGroup = 0);
 
   DECLARE_TRACE();
 
  private:
-  void timerFired(TimerBase*) { update(false); }
+  void timerFired(TimerBase*) {
+    update(Optional<CompositorElementIdSet>(), false);
+  }
 
   HeapVector<Member<Animation>> m_pending;
   HeapVector<Member<Animation>> m_waitingForCompositorAnimationStart;
   TaskRunnerTimer<CompositorPendingAnimations> m_timer;
   int m_compositorGroup;
 };
 
 }  // namespace blink
 
 #endif