CC Animations: Make LayerAnimationController creation optional

cc/trees/layer_tree_host_unittest_animation.cc

Index: cc/trees/layer_tree_host_unittest_animation.cc
diff --git a/cc/trees/layer_tree_host_unittest_animation.cc b/cc/trees/layer_tree_host_unittest_animation.cc
index 93202a0a57fdf7536e3f43f76ad98a48e5dc8add..564a1bb06b809f412542b2c10af535444dad39b2 100644
--- a/cc/trees/layer_tree_host_unittest_animation.cc
+++ b/cc/trees/layer_tree_host_unittest_animation.cc
@@ -282,8 +282,8 @@ class LayerTreeHostAnimationTestSynchronizeAnimationStartTimes
     LayerTreeHostAnimationTest::SetupTree();
     content_ = FakeContentLayer::Create(&client_);
     content_->SetBounds(gfx::Size(4, 4));
-    content_->set_layer_animation_delegate(this);
     layer_tree_host()->root_layer()->AddChild(content_);
+    content_->set_layer_animation_delegate(this);
   }
 
   void BeginTest() override { PostAddAnimationToMainThread(content_.get()); }
@@ -411,6 +411,8 @@ class LayerTreeHostAnimationTestLayerAddedWithAnimation
   void DidCommit() override {
     if (layer_tree_host()->source_frame_number() == 1) {
       scoped_refptr<Layer> layer = Layer::Create();
+      layer->RegisterForAnimations(layer_tree_host()->animation_registrar(),
+                                   layer_tree_host()->settings());
       layer->set_layer_animation_delegate(this);
 
       // Any valid AnimationCurve will do here.
@@ -560,8 +562,8 @@ class LayerTreeHostAnimationTestRunAnimationWhenNotCanDraw
     LayerTreeHostAnimationTest::SetupTree();
     content_ = FakeContentLayer::Create(&client_);
     content_->SetBounds(gfx::Size(4, 4));
-    content_->set_layer_animation_delegate(this);
     layer_tree_host()->root_layer()->AddChild(content_);
+    content_->set_layer_animation_delegate(this);
   }
 
   void BeginTest() override {
@@ -600,8 +602,8 @@ class LayerTreeHostAnimationTestCheckerboardDoesntStartAnimations
     LayerTreeHostAnimationTest::SetupTree();
     content_ = FakeContentLayer::Create(&client_);
     content_->SetBounds(gfx::Size(4, 4));
-    content_->set_layer_animation_delegate(this);
     layer_tree_host()->root_layer()->AddChild(content_);
+    content_->set_layer_animation_delegate(this);
   }
 
   void InitializeSettings(LayerTreeSettings* settings) override {