[Sketch] CC Animations: Torpedo the old intrusive animation system.

ui/compositor/compositor.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/compositor.h"
 
 #include <algorithm>
 #include <deque>
 
 #include "base/bind.h"
@@ skipping 120 matching lines @@
 
   settings.impl_side_painting = IsUIImplSidePaintingEnabled();
   settings.use_display_lists = IsUISlimmingPaintEnabled();
   settings.use_zero_copy = IsUIZeroCopyEnabled();
   settings.use_one_copy = IsUIOneCopyEnabled();
   settings.use_image_texture_target = context_factory_->GetImageTextureTarget();
   // Note: gathering of pixel refs is only needed when using multiple
   // raster threads.
   settings.gather_pixel_refs = false;
 
-  settings.use_compositor_animation_timelines =
-      command_line->HasSwitch(switches::kUIEnableCompositorAnimationTimelines);
-
   base::TimeTicks before_create = base::TimeTicks::Now();
   host_ = cc::LayerTreeHost::CreateSingleThreaded(
       this, this, context_factory_->GetSharedBitmapManager(),
       context_factory_->GetGpuMemoryBufferManager(),
       context_factory_->GetTaskGraphRunner(), settings, task_runner_, nullptr);
   UMA_HISTOGRAM_TIMES("GPU.CreateBrowserCompositor",
                       base::TimeTicks::Now() - before_create);
 
-  if (settings.use_compositor_animation_timelines) {
-    animation_timeline_ = cc::AnimationTimeline::Create(
-        cc::AnimationIdProvider::NextTimelineId());
-    host_->animation_host()->AddAnimationTimeline(animation_timeline_.get());
-  }
+  animation_timeline_ =
+      cc::AnimationTimeline::Create(cc::AnimationIdProvider::NextTimelineId());
+  host_->animation_host()->AddAnimationTimeline(animation_timeline_.get());
+
   host_->SetRootLayer(root_web_layer_);
   host_->set_surface_id_namespace(surface_id_allocator_->id_namespace());
   host_->SetLayerTreeHostClientReady();
 }
 
 Compositor::~Compositor() {
   TRACE_EVENT0("shutdown", "Compositor::destructor");
 
   CancelCompositorLock();
   DCHECK(!compositor_lock_);
 
   FOR_EACH_OBSERVER(CompositorObserver, observer_list_,
                     OnCompositingShuttingDown(this));
 
   DCHECK(begin_frame_observer_list_.empty());
 
   if (root_layer_)
     root_layer_->ResetCompositor();
 
-  if (animation_timeline_)
-    host_->animation_host()->RemoveAnimationTimeline(animation_timeline_.get());
+  host_->animation_host()->RemoveAnimationTimeline(animation_timeline_.get());
 
   // Stop all outstanding draws before telling the ContextFactory to tear
   // down any contexts that the |host_| may rely upon.
   host_.reset();
 
   context_factory_->RemoveCompositor(this);
 }
 
 void Compositor::SetOutputSurface(
     scoped_ptr<cc::OutputSurface> output_surface) {
@@ skipping 11 matching lines @@
     root_layer_->ResetCompositor();
   root_layer_ = root_layer;
   if (root_layer_ && !root_layer_->GetCompositor())
     root_layer_->SetCompositor(this);
   root_web_layer_->RemoveAllChildren();
   if (root_layer_)
     root_layer_->SetCompositorRootCCLayer(root_web_layer_);
 }
 
 cc::AnimationTimeline* Compositor::GetAnimationTimeline() const {
-  DCHECK(animation_timeline_);
   return animation_timeline_.get();
 }
 
 void Compositor::SetHostHasTransparentBackground(
     bool host_has_transparent_background) {
   host_->set_has_transparent_background(host_has_transparent_background);
 }
 
 void Compositor::ScheduleFullRedraw() {
   // TODO(enne): Some callers (mac) call this function expecting that it
@@ skipping 226 matching lines @@
                     observer_list_,
                     OnCompositingLockStateChanged(this));
 }
 
 void Compositor::CancelCompositorLock() {
   if (compositor_lock_)
     compositor_lock_->CancelLock();
 }
 
 }  // namespace ui