compositor: Add rAF-like functionality for the UI.

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 271 matching lines @@
 }
 
 void Compositor::RemoveObserver(CompositorObserver* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
 bool Compositor::HasObserver(CompositorObserver* observer) {
   return observer_list_.HasObserver(observer);
 }
 
+void Compositor::AddAnimationObserver(CompositorAnimationObserver* observer) {
+  animation_observer_list_.AddObserver(observer);
+  host_->SetNeedsAnimate();
+}
+
+void Compositor::RemoveAnimationObserver(
+    CompositorAnimationObserver* observer) {
+  animation_observer_list_.RemoveObserver(observer);
+}
+
+bool Compositor::HasAnimationObserver(CompositorAnimationObserver* observer) {
+  return animation_observer_list_.HasObserver(observer);
+}
+
 void Compositor::Animate(base::TimeTicks frame_begin_time) {
-  layer_animator_collection_.Progress(frame_begin_time);
-  if (layer_animator_collection_.HasActiveAnimators())
+  FOR_EACH_OBSERVER(CompositorAnimationObserver,
+                    animation_observer_list_,
+                    OnAnimationStep(frame_begin_time));
+  if (animation_observer_list_.might_have_observers())
     host_->SetNeedsAnimate();
 }
 
 void Compositor::Layout() {
   // We're sending damage that will be addressed during this composite
   // cycle, so we don't need to schedule another composite to address it.
   disable_schedule_composite_ = true;
   if (root_layer_)
     root_layer_->SendDamagedRects();
   disable_schedule_composite_ = false;
@@ skipping 48 matching lines @@
       NotifyEnd();
       swap_state_ = SWAP_COMPLETED;
     }
   }
 
   FOR_EACH_OBSERVER(CompositorObserver,
                     observer_list_,
                     OnCompositingAborted(this));
 }
 
-void Compositor::ScheduleAnimationForLayerCollection() {
-  host_->SetNeedsAnimate();
-}
-
 const cc::LayerTreeDebugState& Compositor::GetLayerTreeDebugState() const {
   return host_->debug_state();
 }
 
 void Compositor::SetLayerTreeDebugState(
     const cc::LayerTreeDebugState& debug_state) {
   host_->SetDebugState(debug_state);
 }
 
 scoped_refptr<CompositorLock> Compositor::GetCompositorLock() {
@@ skipping 34 matching lines @@
     // CompositorObservers to be notified before starting another
     // draw cycle.
     ScheduleDraw();
   }
   FOR_EACH_OBSERVER(CompositorObserver,
                     observer_list_,
                     OnCompositingEnded(this));
 }
 
 }  // namespace ui