cc : Track opacity animation changes on effect tree

cc/animation/element_animations.cc

Index: cc/animation/element_animations.cc
diff --git a/cc/animation/element_animations.cc b/cc/animation/element_animations.cc
index be4b9687d99075a6e8b8aa7cc5c3bdb9e74e164b..d05183b6e20e6640d321110927a9e0351e9afa89 100644
--- a/cc/animation/element_animations.cc
+++ b/cc/animation/element_animations.cc
@@ -67,6 +67,7 @@ void ElementAnimations::InitAffectedElementTypes() {
 void ElementAnimations::ClearAffectedElementTypes() {
   DCHECK(animation_host_);
 
+  OnOpacityIsCurrentlyAnimatingChanged(false);
   if (has_element_in_active_list())
     OnTransformIsPotentiallyAnimatingChanged(ElementListType::ACTIVE, false);
   set_has_element_in_active_list(false);
@@ -154,6 +155,9 @@ void ElementAnimations::Animate(base::TimeTicks monotonic_time) {
     StartAnimations(monotonic_time);
   TickAnimations(monotonic_time);
   last_tick_time_ = monotonic_time;
+  bool some_opacity_animation_is_now_running = !AllOpacityAnimationsEnded();
+  if (some_opacity_animation_is_now_running)
+    OnOpacityIsCurrentlyAnimatingChanged(true);
 }
 
 void ElementAnimations::AccumulatePropertyUpdates(
@@ -763,17 +767,21 @@ void ElementAnimations::PromoteStartedAnimations(base::TimeTicks monotonic_time,
 
 void ElementAnimations::MarkFinishedAnimations(base::TimeTicks monotonic_time) {
   bool finished_transform_animation = false;
+  bool finished_opacity_animation = false;
   for (size_t i = 0; i < animations_.size(); ++i) {
     if (!animations_[i]->is_finished() &&
         animations_[i]->IsFinishedAt(monotonic_time)) {
       animations_[i]->SetRunState(Animation::FINISHED, monotonic_time);
-      if (animations_[i]->target_property() == TargetProperty::TRANSFORM) {
+      if (animations_[i]->target_property() == TargetProperty::TRANSFORM)
         finished_transform_animation = true;
-      }
+      else if (animations_[i]->target_property() == TargetProperty::OPACITY)
+        finished_opacity_animation = true;
     }
   }
   if (finished_transform_animation)
     UpdatePotentiallyAnimatingTransform();
+  if (finished_opacity_animation && AllOpacityAnimationsEnded())
+    OnOpacityIsCurrentlyAnimatingChanged(false);
 }
 
 void ElementAnimations::MarkAnimationsForDeletion(
@@ -1110,6 +1118,15 @@ void ElementAnimations::UpdatePotentiallyAnimatingTransform() {
       changed_for_active_elements, changed_for_pending_elements);
 }
 
+bool ElementAnimations::AllOpacityAnimationsEnded() {
+  for (const auto& animation : animations_) {
+    if (!animation->is_finished() && animation->InEffect(last_tick_time_) &&
+        animation->target_property() == TargetProperty::OPACITY)
+      return false;
+  }
+  return true;
+}
+
 bool ElementAnimations::HasActiveAnimation() const {
   for (size_t i = 0; i < animations_.size(); ++i) {
     if (!animations_[i]->is_finished())
@@ -1164,6 +1181,7 @@ void ElementAnimations::PauseAnimation(int animation_id,
 
 void ElementAnimations::RemoveAnimation(int animation_id) {
   bool removed_transform_animation = false;
+  bool removed_opacity_animation = false;
   // Since we want to use the animations that we're going to remove, we need to
   // use a stable_parition here instead of remove_if. Remove_if leaves the
   // removed items in an unspecified state.
@@ -1178,6 +1196,9 @@ void ElementAnimations::RemoveAnimation(int animation_id) {
     } else if ((*it)->target_property() == TargetProperty::TRANSFORM &&
                !(*it)->is_finished()) {
       removed_transform_animation = true;
+    } else if ((*it)->target_property() == TargetProperty::OPACITY &&
+               !(*it)->is_finished()) {
+      removed_opacity_animation = true;
     }
   }
 
@@ -1185,19 +1206,26 @@ void ElementAnimations::RemoveAnimation(int animation_id) {
   UpdateActivation(NORMAL_ACTIVATION);
   if (removed_transform_animation)
     UpdatePotentiallyAnimatingTransform();
+  if (removed_opacity_animation && AllOpacityAnimationsEnded())
+    OnOpacityIsCurrentlyAnimatingChanged(false);
 }
 
 void ElementAnimations::AbortAnimation(int animation_id) {
   bool aborted_transform_animation = false;
+  bool aborted_opacity_animation = false;
   if (Animation* animation = GetAnimationById(animation_id)) {
     if (!animation->is_finished()) {
       animation->SetRunState(Animation::ABORTED, last_tick_time_);
       if (animation->target_property() == TargetProperty::TRANSFORM)
         aborted_transform_animation = true;
+      else if (animation->target_property() == TargetProperty::OPACITY)
+        aborted_opacity_animation = true;
     }
   }
   if (aborted_transform_animation)
     UpdatePotentiallyAnimatingTransform();
+  if (aborted_opacity_animation && AllOpacityAnimationsEnded())
+    OnOpacityIsCurrentlyAnimatingChanged(false);
 }
 
 void ElementAnimations::AbortAnimations(TargetProperty::Type target_property,
@@ -1206,6 +1234,7 @@ void ElementAnimations::AbortAnimations(TargetProperty::Type target_property,
     DCHECK(target_property == TargetProperty::SCROLL_OFFSET);
 
   bool aborted_transform_animation = false;
+  bool aborted_opacity_animation = false;
   for (size_t i = 0; i < animations_.size(); ++i) {
     if (animations_[i]->target_property() == target_property &&
         !animations_[i]->is_finished()) {
@@ -1219,10 +1248,14 @@ void ElementAnimations::AbortAnimations(TargetProperty::Type target_property,
       }
       if (target_property == TargetProperty::TRANSFORM)
         aborted_transform_animation = true;
+      else if (target_property == TargetProperty::OPACITY)
+        aborted_opacity_animation = true;
     }
   }
   if (aborted_transform_animation)
     UpdatePotentiallyAnimatingTransform();
+  if (aborted_opacity_animation && AllOpacityAnimationsEnded())
+    OnOpacityIsCurrentlyAnimatingChanged(false);
 }
 
 Animation* ElementAnimations::GetAnimation(
@@ -1298,6 +1331,17 @@ void ElementAnimations::OnTransformIsPotentiallyAnimatingChanged(
                                                       is_animating);
 }
 
+void ElementAnimations::OnOpacityIsCurrentlyAnimatingChanged(
+    bool is_currently_animating) {
+  DCHECK(element_id());
+  DCHECK(animation_host());
+  if (animation_host()->mutator_host_client())
+    animation_host()
+        ->mutator_host_client()
+        ->ElementOpacityIsCurrentlyAnimatingChanged(element_id(),
+                                                    is_currently_animating);
+}
+
 void ElementAnimations::NotifyPlayersAnimationStarted(
     base::TimeTicks monotonic_time,
     TargetProperty::Type target_property,