CC Animations: Enable external animation host for ui::Compositor (Aura)

ui/compositor/layer.cc

 // Copyright (c) 2012 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.
 
 #include "ui/compositor/layer.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 114 matching lines @@
 }
 
 // static
 const cc::LayerSettings& Layer::UILayerSettings() {
   return g_ui_layer_settings.Get();
 }
 
 // static
 void Layer::InitializeUILayerSettings() {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(switches::kUIEnableCompositorAnimationTimelines))
-    g_ui_layer_settings.Get().use_compositor_animation_timelines = true;
+  g_ui_layer_settings.Get().use_compositor_animation_timelines =
+      !command_line->HasSwitch(
+          switches::kUIDisableCompositorAnimationTimelines);
 }
 
 const Compositor* Layer::GetCompositor() const {
   return GetRoot(this)->compositor_;
 }
 
 float Layer::opacity() const {
   return cc_layer_->opacity();
 }
 
@@ skipping 950 matching lines @@
     animator_->ResetCompositor(compositor);
     if (animator_->is_animating())
       animator_->RemoveFromCollection(collection);
   }
 
   for (auto* child : children_)
     child->ResetCompositorForAnimatorsInTree(compositor);
 }
 
 }  // namespace ui