Revert of Moving background animation ticking from LayerTreeHostImpl into the Scheduler.

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 65e8dd27a35de390d404d951d5b701fc56dc5224..37830f601dd0ce1351ecddc55fb0bd6b59b7dd1c 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -176,7 +176,16 @@
   TRACE_EVENT0("cc", "ThreadProxy::SetVisibleOnImplThread");
   impl().layer_tree_host_impl->SetVisible(visible);
   impl().scheduler->SetVisible(visible);
+  UpdateBackgroundAnimateTicking();
   completion->Signal();
+}
+
+void ThreadProxy::UpdateBackgroundAnimateTicking() {
+  bool should_background_tick =
+      !impl().scheduler->WillDrawIfNeeded() &&
+      impl().layer_tree_host_impl->active_tree()->root_layer();
+  impl().layer_tree_host_impl->UpdateBackgroundAnimateTicking(
+      should_background_tick);
 }
 
 void ThreadProxy::DidLoseOutputSurface() {
@@ -349,6 +358,7 @@
       "cc", "ThreadProxy::OnCanDrawStateChanged", "can_draw", can_draw);
   DCHECK(IsImplThread());
   impl().scheduler->SetCanDraw(can_draw);
+  UpdateBackgroundAnimateTicking();
 }
 
 void ThreadProxy::NotifyReadyToActivate() {
@@ -917,22 +927,9 @@
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionAnimate");
   DCHECK(IsImplThread());
 
-  // Don't animate if there is no root layer.
-  // TODO(mithro): Both Animate and UpdateAnimationState already have a
-  // "!active_tree_->root_layer()" check?
-  if (!impl().layer_tree_host_impl->active_tree()->root_layer()) {
-    return;
-  }
-
   impl().animation_time =
       impl().layer_tree_host_impl->CurrentBeginFrameArgs().frame_time;
   impl().layer_tree_host_impl->Animate(impl().animation_time);
-
-  // If animations are not visible, update the state now as
-  // ScheduledActionDrawAndSwapIfPossible will never be called.
-  if (!impl().layer_tree_host_impl->AnimationsAreVisible()) {
-    impl().layer_tree_host_impl->UpdateAnimationState(true);
-  }
 }
 
 void ThreadProxy::ScheduledActionCommit() {
@@ -975,6 +972,8 @@
   impl().layer_tree_host_impl->CommitComplete();
 
   SetInputThrottledUntilCommitOnImplThread(false);
+
+  UpdateBackgroundAnimateTicking();
 
   impl().next_frame_is_newly_committed_frame = true;
 
@@ -1353,6 +1352,8 @@
     impl().completion_event_for_commit_held_on_tree_activation = NULL;
   }
 
+  UpdateBackgroundAnimateTicking();
+
   impl().timing_history.DidActivateSyncTree();
 }