Revert of Use element id's for animations

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 f865ef9c52eb3ab1e83402edda3a5d3019cc0e0c..3f50091227d4390ccd3586e39967ad70d964ebf6 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -949,14 +949,6 @@
       has_fixed_raster_scale_potential_performance_regression);
 }
 
-static void SetElementIdForTesting(Layer* layer) {
-  layer->SetElementId(LayerIdToElementIdForTesting(layer->id()));
-}
-
-void LayerTreeHost::SetElementIdsForTesting() {
-  LayerTreeHostCommon::CallFunctionForEveryLayer(this, SetElementIdForTesting);
-}
-
 bool LayerTreeHost::UsingSharedMemoryResources() {
   return GetRendererCapabilities().using_shared_memory_resources;
 }
@@ -1275,26 +1267,7 @@
 
 Layer* LayerTreeHost::LayerById(int id) const {
   LayerIdMap::const_iterator iter = layer_id_map_.find(id);
-  return iter != layer_id_map_.end() ? iter->second : nullptr;
-}
-
-Layer* LayerTreeHost::LayerByElementId(ElementId element_id) const {
-  ElementLayersMap::const_iterator iter = element_layers_map_.find(element_id);
-  return iter != element_layers_map_.end() ? iter->second : nullptr;
-}
-
-void LayerTreeHost::AddToElementMap(Layer* layer) {
-  if (!layer->element_id())
-    return;
-
-  element_layers_map_[layer->element_id()] = layer;
-}
-
-void LayerTreeHost::RemoveFromElementMap(Layer* layer) {
-  if (!layer->element_id())
-    return;
-
-  element_layers_map_.erase(layer->element_id());
+  return iter != layer_id_map_.end() ? iter->second : NULL;
 }
 
 void LayerTreeHost::AddLayerShouldPushProperties(Layer* layer) {
@@ -1318,26 +1291,20 @@
   DCHECK(!LayerById(layer->id()));
   DCHECK(!in_paint_layer_contents_);
   layer_id_map_[layer->id()] = layer;
-  if (layer->element_id()) {
-    animation_host_->RegisterElement(layer->element_id(),
-                                     ElementListType::ACTIVE);
-  }
+  animation_host_->RegisterElement(layer->id(), ElementListType::ACTIVE);
 }
 
 void LayerTreeHost::UnregisterLayer(Layer* layer) {
   DCHECK(LayerById(layer->id()));
   DCHECK(!in_paint_layer_contents_);
-  if (layer->element_id()) {
-    animation_host_->UnregisterElement(layer->element_id(),
-                                       ElementListType::ACTIVE);
-  }
+  animation_host_->UnregisterElement(layer->id(), ElementListType::ACTIVE);
   RemoveLayerShouldPushProperties(layer);
   layer_id_map_.erase(layer->id());
 }
 
 bool LayerTreeHost::IsElementInList(ElementId element_id,
                                     ElementListType list_type) const {
-  return list_type == ElementListType::ACTIVE && LayerByElementId(element_id);
+  return list_type == ElementListType::ACTIVE && LayerById(element_id);
 }
 
 void LayerTreeHost::SetMutatorsNeedCommit() {
@@ -1351,7 +1318,7 @@
 void LayerTreeHost::SetElementFilterMutated(ElementId element_id,
                                             ElementListType list_type,
                                             const FilterOperations& filters) {
-  Layer* layer = LayerByElementId(element_id);
+  Layer* layer = LayerById(element_id);
   DCHECK(layer);
   layer->OnFilterAnimated(filters);
 }
@@ -1359,7 +1326,7 @@
 void LayerTreeHost::SetElementOpacityMutated(ElementId element_id,
                                              ElementListType list_type,
                                              float opacity) {
-  Layer* layer = LayerByElementId(element_id);
+  Layer* layer = LayerById(element_id);
   DCHECK(layer);
   layer->OnOpacityAnimated(opacity);
 }
@@ -1368,7 +1335,7 @@
     ElementId element_id,
     ElementListType list_type,
     const gfx::Transform& transform) {
-  Layer* layer = LayerByElementId(element_id);
+  Layer* layer = LayerById(element_id);
   DCHECK(layer);
   layer->OnTransformAnimated(transform);
 }
@@ -1377,7 +1344,7 @@
     ElementId element_id,
     ElementListType list_type,
     const gfx::ScrollOffset& scroll_offset) {
-  Layer* layer = LayerByElementId(element_id);
+  Layer* layer = LayerById(element_id);
   DCHECK(layer);
   layer->OnScrollOffsetAnimated(scroll_offset);
 }
@@ -1387,7 +1354,7 @@
     ElementListType list_type,
     AnimationChangeType change_type,
     bool is_animating) {
-  Layer* layer = LayerByElementId(element_id);
+  Layer* layer = LayerById(element_id);
   if (layer) {
     switch (change_type) {
       case AnimationChangeType::POTENTIAL:
@@ -1409,7 +1376,7 @@
     ElementListType list_type,
     AnimationChangeType change_type,
     bool is_animating) {
-  Layer* layer = LayerByElementId(element_id);
+  Layer* layer = LayerById(element_id);
   if (layer) {
     switch (change_type) {
       case AnimationChangeType::POTENTIAL:
@@ -1428,84 +1395,83 @@
 
 gfx::ScrollOffset LayerTreeHost::GetScrollOffsetForAnimation(
     ElementId element_id) const {
-  Layer* layer = LayerByElementId(element_id);
+  Layer* layer = LayerById(element_id);
   DCHECK(layer);
   return layer->ScrollOffsetForAnimation();
 }
 
 bool LayerTreeHost::ScrollOffsetAnimationWasInterrupted(
     const Layer* layer) const {
-  return animation_host_->ScrollOffsetAnimationWasInterrupted(
-      layer->element_id());
+  return animation_host_->ScrollOffsetAnimationWasInterrupted(layer->id());
 }
 
 bool LayerTreeHost::IsAnimatingFilterProperty(const Layer* layer) const {
-  return animation_host_->IsAnimatingFilterProperty(layer->element_id(),
+  return animation_host_->IsAnimatingFilterProperty(layer->id(),
                                                     ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::IsAnimatingOpacityProperty(const Layer* layer) const {
-  return animation_host_->IsAnimatingOpacityProperty(layer->element_id(),
+  return animation_host_->IsAnimatingOpacityProperty(layer->id(),
                                                      ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::IsAnimatingTransformProperty(const Layer* layer) const {
-  return animation_host_->IsAnimatingTransformProperty(layer->element_id(),
+  return animation_host_->IsAnimatingTransformProperty(layer->id(),
                                                        ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasPotentiallyRunningFilterAnimation(
     const Layer* layer) const {
   return animation_host_->HasPotentiallyRunningFilterAnimation(
-      layer->element_id(), ElementListType::ACTIVE);
+      layer->id(), ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasPotentiallyRunningOpacityAnimation(
     const Layer* layer) const {
   return animation_host_->HasPotentiallyRunningOpacityAnimation(
-      layer->element_id(), ElementListType::ACTIVE);
+      layer->id(), ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasPotentiallyRunningTransformAnimation(
     const Layer* layer) const {
   return animation_host_->HasPotentiallyRunningTransformAnimation(
-      layer->element_id(), ElementListType::ACTIVE);
+      layer->id(), ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::HasOnlyTranslationTransforms(const Layer* layer) const {
-  return animation_host_->HasOnlyTranslationTransforms(layer->element_id(),
+  return animation_host_->HasOnlyTranslationTransforms(layer->id(),
                                                        ElementListType::ACTIVE);
 }
 
 bool LayerTreeHost::MaximumTargetScale(const Layer* layer,
                                        float* max_scale) const {
   return animation_host_->MaximumTargetScale(
-      layer->element_id(), ElementListType::ACTIVE, max_scale);
+      layer->id(), ElementListType::ACTIVE, max_scale);
 }
 
 bool LayerTreeHost::AnimationStartScale(const Layer* layer,
                                         float* start_scale) const {
   return animation_host_->AnimationStartScale(
-      layer->element_id(), ElementListType::ACTIVE, start_scale);
+      layer->id(), ElementListType::ACTIVE, start_scale);
 }
 
 bool LayerTreeHost::HasAnyAnimationTargetingProperty(
     const Layer* layer,
     TargetProperty::Type property) const {
-  return animation_host_->HasAnyAnimationTargetingProperty(layer->element_id(),
+  return animation_host_->HasAnyAnimationTargetingProperty(layer->id(),
                                                            property);
 }
 
 bool LayerTreeHost::AnimationsPreserveAxisAlignment(const Layer* layer) const {
-  return animation_host_->AnimationsPreserveAxisAlignment(layer->element_id());
+  return animation_host_->AnimationsPreserveAxisAlignment(layer->id());
 }
 
 bool LayerTreeHost::HasAnyAnimation(const Layer* layer) const {
-  return animation_host_->HasAnyAnimation(layer->element_id());
+  return animation_host_->HasAnyAnimation(layer->id());
 }
 
 bool LayerTreeHost::HasActiveAnimationForTesting(const Layer* layer) const {
-  return animation_host_->HasActiveAnimationForTesting(layer->element_id());
+  return animation_host_->HasActiveAnimationForTesting(layer->id());
 }
 
 bool LayerTreeHost::IsSingleThreaded() const {