Refactoring the way begin frame sources inside scheduler work.

cc/trees/single_thread_proxy.cc

Index: cc/trees/single_thread_proxy.cc
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index 157ecbeeb5ec4695591b26c69766a539a8227394..b965dcd7cb85bea4e471d8d0b7a46d3402db3e65 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -79,9 +79,6 @@ void SingleThreadProxy::SetVisible(bool visible) {
   TRACE_EVENT0("cc", "SingleThreadProxy::SetVisible");
   DebugScopedSetImplThread impl(this);
   layer_tree_host_impl_->SetVisible(visible);
-
-  // Changing visibility could change ShouldComposite().
-  UpdateBackgroundAnimateTicking();
 }
 
 void SingleThreadProxy::CreateAndInitializeOutputSurface() {
@@ -232,7 +229,6 @@ void SingleThreadProxy::OnCanDrawStateChanged(bool can_draw) {
   TRACE_EVENT1(
       "cc", "SingleThreadProxy::OnCanDrawStateChanged", "can_draw", can_draw);
   DCHECK(Proxy::IsImplThread());
-  UpdateBackgroundAnimateTicking();
 }
 
 void SingleThreadProxy::NotifyReadyToActivate() {
@@ -412,12 +408,6 @@ bool SingleThreadProxy::ShouldComposite() const {
          layer_tree_host_impl_->CanDraw();
 }
 
-void SingleThreadProxy::UpdateBackgroundAnimateTicking() {
-  DCHECK(Proxy::IsImplThread());
-  layer_tree_host_impl_->UpdateBackgroundAnimateTicking(
-      !ShouldComposite() && layer_tree_host_impl_->active_tree()->root_layer());
-}
-
 bool SingleThreadProxy::DoComposite(
     base::TimeTicks frame_begin_time,
     LayerTreeHostImpl::FrameData* frame) {
@@ -434,13 +424,11 @@ bool SingleThreadProxy::DoComposite(
     // DrawLayers() depends on the result of PrepareToDraw(), it is guarded on
     // CanDraw() as well.
     if (!ShouldComposite()) {
-      UpdateBackgroundAnimateTicking();
       return false;
     }
 
     layer_tree_host_impl_->Animate(
         layer_tree_host_impl_->CurrentFrameTimeTicks());
-    UpdateBackgroundAnimateTicking();
 
     if (!layer_tree_host_impl_->IsContextLost()) {
       layer_tree_host_impl_->PrepareToDraw(frame);