CC Animation: Use ElementId to attach CC animation players.

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index fee2d6c61e4f92a745574b96d3008c01245076af..f26d8484a57b6f57e271e524def30574fbf2b07f 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -1270,6 +1270,16 @@ Layer* LayerTreeHost::LayerById(int id) const {
   return iter != layer_id_map_.end() ? iter->second : NULL;
 }
 
+Layer* LayerTreeHost::LayerForElementId(ElementId element_id) const {
+  auto iter = element_id_to_layer_map_.find(element_id);
+  return iter != element_id_to_layer_map_.end() ? iter->second.main : nullptr;
+}
+
+Layer* LayerTreeHost::ScrollLayerForElementId(ElementId element_id) const {
+  auto iter = element_id_to_layer_map_.find(element_id);
+  return iter != element_id_to_layer_map_.end() ? iter->second.scroll : nullptr;
+}
+
 void LayerTreeHost::AddLayerShouldPushProperties(Layer* layer) {
   layers_that_should_push_properties_.insert(layer);
 }
@@ -1291,20 +1301,56 @@ void LayerTreeHost::RegisterLayer(Layer* layer) {
   DCHECK(!LayerById(layer->id()));
   DCHECK(!in_paint_layer_contents_);
   layer_id_map_[layer->id()] = layer;
-  animation_host_->RegisterElement(layer->id(), ElementListType::ACTIVE);
 }
 
 void LayerTreeHost::UnregisterLayer(Layer* layer) {
   DCHECK(LayerById(layer->id()));
   DCHECK(!in_paint_layer_contents_);
-  animation_host_->UnregisterElement(layer->id(), ElementListType::ACTIVE);
   RemoveLayerShouldPushProperties(layer);
   layer_id_map_.erase(layer->id());
 }
 
+void LayerTreeHost::RegisterLayerForElementId(Layer* layer) {
+  DCHECK(layer->element_id());
+  ElementLayers& element_layers = element_id_to_layer_map_[layer->element_id()];
+  if (layer->scrollable()) {
+    DCHECK(!element_layers.scroll);
+    element_layers.scroll = layer;
+  } else {
+    DCHECK(!element_layers.main);
+    element_layers.main = layer;
+  }
+  animation_host_->RegisterElement(layer->element_id(),
+                                   ElementListType::ACTIVE);
+}
+
+void LayerTreeHost::UnregisterLayerForElementId(Layer* layer) {
+  DCHECK(layer->element_id());
+  animation_host_->UnregisterElement(layer->element_id(),
+                                     ElementListType::ACTIVE);
+
+  auto iter = element_id_to_layer_map_.find(layer->element_id());
+  if (iter == element_id_to_layer_map_.end())
+    return;
+
+  ElementLayers& element_layers = iter->second;
+  if (layer->scrollable()) {
+    DCHECK_EQ(element_layers.scroll, layer);
+    element_layers.scroll = nullptr;
+  } else {
+    DCHECK_EQ(element_layers.main, layer);
+    element_layers.main = nullptr;
+  }
+
+  if (!element_layers.main && !element_layers.scroll)
+    element_id_to_layer_map_.erase(layer->element_id());
+}
+
 bool LayerTreeHost::IsElementInList(ElementId element_id,
                                     ElementListType list_type) const {
-  return list_type == ElementListType::ACTIVE && LayerById(element_id);
+  return list_type == ElementListType::ACTIVE &&
+         element_id_to_layer_map_.find(element_id) !=
+             element_id_to_layer_map_.end();
 }
 
 void LayerTreeHost::SetMutatorsNeedCommit() {
@@ -1318,7 +1364,7 @@ void LayerTreeHost::SetMutatorsNeedRebuildPropertyTrees() {
 void LayerTreeHost::SetElementFilterMutated(ElementId element_id,
                                             ElementListType list_type,
                                             const FilterOperations& filters) {
-  Layer* layer = LayerById(element_id);
+  Layer* layer = LayerForElementId(element_id);
   DCHECK(layer);
   layer->OnFilterAnimated(filters);
 }
@@ -1326,7 +1372,7 @@ void LayerTreeHost::SetElementFilterMutated(ElementId element_id,
 void LayerTreeHost::SetElementOpacityMutated(ElementId element_id,
                                              ElementListType list_type,
                                              float opacity) {
-  Layer* layer = LayerById(element_id);
+  Layer* layer = LayerForElementId(element_id);
   DCHECK(layer);
   layer->OnOpacityAnimated(opacity);
 }
@@ -1335,7 +1381,7 @@ void LayerTreeHost::SetElementTransformMutated(
     ElementId element_id,
     ElementListType list_type,
     const gfx::Transform& transform) {
-  Layer* layer = LayerById(element_id);
+  Layer* layer = LayerForElementId(element_id);
   DCHECK(layer);
   layer->OnTransformAnimated(transform);
 }
@@ -1344,7 +1390,7 @@ void LayerTreeHost::SetElementScrollOffsetMutated(
     ElementId element_id,
     ElementListType list_type,
     const gfx::ScrollOffset& scroll_offset) {
-  Layer* layer = LayerById(element_id);
+  Layer* layer = ScrollLayerForElementId(element_id);
   DCHECK(layer);
   layer->OnScrollOffsetAnimated(scroll_offset);
 }
@@ -1353,90 +1399,133 @@ void LayerTreeHost::ElementTransformIsPotentiallyAnimatingChanged(
     ElementId element_id,
     ElementListType list_type,
     bool is_animating) {
-  Layer* layer = LayerById(element_id);
-  DCHECK(layer);
-  layer->OnTransformIsPotentiallyAnimatingChanged(is_animating);
+  Layer* layer = LayerForElementId(element_id);
+  if (layer)
+    layer->OnTransformIsPotentiallyAnimatingChanged(is_animating);
 }
 
 gfx::ScrollOffset LayerTreeHost::GetScrollOffsetForAnimation(
     ElementId element_id) const {
-  Layer* layer = LayerById(element_id);
+  Layer* layer = ScrollLayerForElementId(element_id);
   DCHECK(layer);
   return layer->ScrollOffsetForAnimation();
 }
 
 bool LayerTreeHost::ScrollOffsetAnimationWasInterrupted(
     const Layer* layer) const {
-  return animation_host_->ScrollOffsetAnimationWasInterrupted(layer->id());
+  if (!layer->element_id())
+    return false;
+
+  return animation_host_->ScrollOffsetAnimationWasInterrupted(
+      layer->element_id());
 }
 
 bool LayerTreeHost::IsAnimatingFilterProperty(const Layer* layer) const {
-  return animation_host_->IsAnimatingFilterProperty(layer->id(),
+  if (!layer->element_id())
+    return false;
+
+  return animation_host_->IsAnimatingFilterProperty(layer->element_id(),
                                                     ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::IsAnimatingOpacityProperty(const Layer* layer) const {
-  return animation_host_->IsAnimatingOpacityProperty(layer->id(),
+  if (!layer->element_id())
+    return false;
+
+  return animation_host_->IsAnimatingOpacityProperty(layer->element_id(),
                                                      ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::IsAnimatingTransformProperty(const Layer* layer) const {
-  return animation_host_->IsAnimatingTransformProperty(layer->id(),
+  if (!layer->element_id())
+    return false;
+
+  return animation_host_->IsAnimatingTransformProperty(layer->element_id(),
                                                        ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasPotentiallyRunningFilterAnimation(
     const Layer* layer) const {
+  if (!layer->element_id())
+    return false;
+
   return animation_host_->HasPotentiallyRunningFilterAnimation(
-      layer->id(), ElementListType::ACTIVE);
+      layer->element_id(), ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasPotentiallyRunningOpacityAnimation(
     const Layer* layer) const {
+  if (!layer->element_id())
+    return false;
+
   return animation_host_->HasPotentiallyRunningOpacityAnimation(
-      layer->id(), ElementListType::ACTIVE);
+      layer->element_id(), ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasPotentiallyRunningTransformAnimation(
     const Layer* layer) const {
+  if (!layer->element_id())
+    return false;
+
   return animation_host_->HasPotentiallyRunningTransformAnimation(
-      layer->id(), ElementListType::ACTIVE);
+      layer->element_id(), ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasOnlyTranslationTransforms(const Layer* layer) const {
-  return animation_host_->HasOnlyTranslationTransforms(layer->id(),
+  if (!layer->element_id())
+    return true;
+
+  return animation_host_->HasOnlyTranslationTransforms(layer->element_id(),
                                                        ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::MaximumTargetScale(const Layer* layer,
                                        float* max_scale) const {
+  if (!layer->element_id())
+    return true;
+
   return animation_host_->MaximumTargetScale(
-      layer->id(), ElementListType::ACTIVE, max_scale);
+      layer->element_id(), ElementListType::ACTIVE, max_scale);
 }
 
 bool LayerTreeHost::AnimationStartScale(const Layer* layer,
                                         float* start_scale) const {
+  if (!layer->element_id())
+    return true;
+
   return animation_host_->AnimationStartScale(
-      layer->id(), ElementListType::ACTIVE, start_scale);
+      layer->element_id(), ElementListType::ACTIVE, start_scale);
 }
 
 bool LayerTreeHost::HasAnyAnimationTargetingProperty(
     const Layer* layer,
     TargetProperty::Type property) const {
-  return animation_host_->HasAnyAnimationTargetingProperty(layer->id(),
+  if (!layer->element_id())
+    return false;
+
+  return animation_host_->HasAnyAnimationTargetingProperty(layer->element_id(),
                                                            property);
 }
 
 bool LayerTreeHost::AnimationsPreserveAxisAlignment(const Layer* layer) const {
-  return animation_host_->AnimationsPreserveAxisAlignment(layer->id());
+  if (!layer->element_id())
+    return true;
+
+  return animation_host_->AnimationsPreserveAxisAlignment(layer->element_id());
 }
 
 bool LayerTreeHost::HasAnyAnimation(const Layer* layer) const {
-  return animation_host_->HasAnyAnimation(layer->id());
+  if (!layer->element_id())
+    return false;
+
+  return animation_host_->HasAnyAnimation(layer->element_id());
 }
 
 bool LayerTreeHost::HasActiveAnimationForTesting(const Layer* layer) const {
-  return animation_host_->HasActiveAnimationForTesting(layer->id());
+  if (!layer->element_id())
+    return false;
+
+  return animation_host_->HasActiveAnimationForTesting(layer->element_id());
 }
 
 bool LayerTreeHost::IsSingleThreaded() const {