CC Animations: Make LayerAnimationController creation optional

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index 56b8c739e4f24004b59bf8a138f3cd3606cb7bf9..ff2a41ac37120c6c2227af1083f9c38cb35947d1 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -34,11 +34,11 @@ namespace cc {
 
 base::StaticAtomicSequenceNumber g_next_layer_id;
 
-scoped_refptr<Layer> Layer::Create() {
-  return make_scoped_refptr(new Layer());
+scoped_refptr<Layer> Layer::Create(const LayerSettings& settings) {
+  return make_scoped_refptr(new Layer(settings));
 }
 
-Layer::Layer()
+Layer::Layer(const LayerSettings& settings)
     : needs_push_properties_(false),
       num_dependents_need_push_properties_(false),
       stacking_order_changed_(false),
@@ -83,9 +83,11 @@ Layer::Layer()
       raster_scale_(0.f),
       client_(nullptr),
       frame_timing_requests_dirty_(false) {
-  layer_animation_controller_ = LayerAnimationController::Create(layer_id_);
-  layer_animation_controller_->AddValueObserver(this);
-  layer_animation_controller_->set_value_provider(this);
+  if (!settings.use_compositor_animation_timelines) {
+    layer_animation_controller_ = LayerAnimationController::Create(layer_id_);
+    layer_animation_controller_->AddValueObserver(this);
+    layer_animation_controller_->set_value_provider(this);
+  }
 }
 
 Layer::~Layer() {
@@ -96,8 +98,10 @@ Layer::~Layer() {
   // reference to us.
   DCHECK(!layer_tree_host());
 
-  layer_animation_controller_->RemoveValueObserver(this);
-  layer_animation_controller_->remove_value_provider(this);
+  if (layer_animation_controller_) {
+    layer_animation_controller_->RemoveValueObserver(this);
+    layer_animation_controller_->remove_value_provider(this);
+  }
 
   RemoveFromScrollTree();
   RemoveFromClipTree();
@@ -136,9 +140,7 @@ void Layer::SetLayerTreeHost(LayerTreeHost* host) {
     replica_layer_->SetLayerTreeHost(host);
 
   if (host) {
-    layer_animation_controller_->SetAnimationRegistrar(
-        host->animation_registrar());
-
+    RegisterForAnimations(host->animation_registrar());
     if (host->settings().layer_transforms_should_scale_layer_contents)
       reset_raster_scale_to_unknown();
   }
@@ -1350,6 +1352,7 @@ bool Layer::IsActive() const {
 }
 
 bool Layer::AddAnimation(scoped_ptr <Animation> animation) {
+  DCHECK(layer_animation_controller_);
   if (!layer_animation_controller_->animation_registrar())
     return false;
 
@@ -1394,13 +1397,20 @@ bool Layer::HasActiveAnimation() const {
   return layer_animation_controller_->HasActiveAnimation();
 }
 
+void Layer::RegisterForAnimations(AnimationRegistrar* registrar) {
+  if (layer_animation_controller_)
+    layer_animation_controller_->SetAnimationRegistrar(registrar);
+}
+
 void Layer::AddLayerAnimationEventObserver(
     LayerAnimationEventObserver* animation_observer) {
+  DCHECK(layer_animation_controller_);
   layer_animation_controller_->AddEventObserver(animation_observer);
 }
 
 void Layer::RemoveLayerAnimationEventObserver(
     LayerAnimationEventObserver* animation_observer) {
+  DCHECK(layer_animation_controller_);
   layer_animation_controller_->RemoveEventObserver(animation_observer);
 }