CC Animations: Make LayerAnimationController creation optional

cc/trees/layer_tree_settings.cc

Index: cc/trees/layer_tree_settings.cc
diff --git a/cc/trees/layer_tree_settings.cc b/cc/trees/layer_tree_settings.cc
index ce8445e19375183bf17f05c142730448a8d00422..9e82c4bc349ed3793b327133d6d33865194ad441 100644
--- a/cc/trees/layer_tree_settings.cc
+++ b/cc/trees/layer_tree_settings.cc
@@ -13,6 +13,9 @@
 
 namespace cc {
 
+LayerSettings::LayerSettings() : use_compositor_animation_timelines(false) {
+}
+
 LayerTreeSettings::LayerTreeSettings()
     : impl_side_painting(false),
       raster_enabled(true),
@@ -70,8 +73,7 @@ LayerTreeSettings::LayerTreeSettings()
       record_full_layer(false),
       use_display_lists(false),
       verify_property_trees(false),
-      gather_pixel_refs(false),
-      use_compositor_animation_timelines(false) {
+      gather_pixel_refs(false) {
 }
 
 LayerTreeSettings::~LayerTreeSettings() {}