CC Animations: Make LayerAnimationController creation optional

cc/trees/layer_tree_settings.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TREES_LAYER_TREE_SETTINGS_H_
 #define CC_TREES_LAYER_TREE_SETTINGS_H_
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "cc/debug/layer_tree_debug_state.h"
 #include "cc/output/renderer_settings.h"
 #include "cc/scheduler/scheduler_settings.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace cc {
 
+class CC_EXPORT LayerSettings {
+ public:
+  LayerSettings();
+
+  bool use_compositor_animation_timelines;
+};
+
 class CC_EXPORT LayerTreeSettings {
  public:
   LayerTreeSettings();
   ~LayerTreeSettings();
 
   RendererSettings renderer_settings;
   bool impl_side_painting;
   bool raster_enabled;
   bool throttle_frame_production;
   bool single_thread_proxy_scheduler;
@@ skipping 48 matching lines @@
   bool use_zero_copy;
   bool enable_elastic_overscroll;
   unsigned use_image_texture_target;
   bool ignore_root_layer_flings;
   size_t scheduled_raster_task_limit;
   bool use_occlusion_for_tile_prioritization;
   bool record_full_layer;
   bool use_display_lists;
   bool verify_property_trees;
   bool gather_pixel_refs;
-  bool use_compositor_animation_timelines;
+  LayerSettings hud_layer_settings_;
 
   LayerTreeDebugState initial_debug_state;
 
   SchedulerSettings ToSchedulerSettings() const;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_SETTINGS_H_