cc: Define LayerAnimationObserver and allow LayerAnimationObservers to be registered on a Layer

This makes Layers notify each of their 
LayerAnimationObservers whenever an animation is started on
the impl thread. This functionality is needed for threading
ui animations.

BUG=164206


Review URL: https://chromiumcodereview.appspot.com/11605002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@173597 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 0 deletions

diff --git a/cc/layer.h b/cc/layer.h
index ede6120..adca3b2 100644
--- a/cc/layer.h
+++ b/cc/layer.h
@@ -10,9 +10,11 @@
 #include <vector>
 
 #include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
 #include "cc/cc_export.h"
 #include "cc/draw_properties.h"
 #include "cc/layer_animation_controller.h"
+#include "cc/layer_animation_observer.h"
 #include "cc/occlusion_tracker.h"
 #include "cc/region.h"
 #include "cc/render_surface.h"
@@ -277,6 +279,9 @@ public:
     virtual void notifyAnimationStarted(const AnimationEvent&, double wallClockTime);
     virtual void notifyAnimationFinished(double wallClockTime);
 
+    void addLayerAnimationObserver(LayerAnimationObserver* animationObserver);
+    void removeLayerAnimationObserver(LayerAnimationObserver* animationObserver);
+
     virtual Region visibleContentOpaqueRegion() const;
 
     virtual ScrollbarLayer* toScrollbarLayer();
@@ -340,6 +345,7 @@ private:
     LayerTreeHost* m_layerTreeHost;
 
     scoped_ptr<LayerAnimationController> m_layerAnimationController;
+    ObserverList<LayerAnimationObserver> m_layerAnimationObservers;
 
     // Layer properties.
     gfx::Size m_bounds;