Allows observers to be notified when layer animations complete.

ui/gfx/compositor/layer_animation_sequence.cc

Index: ui/gfx/compositor/layer_animation_sequence.cc
diff --git a/ui/gfx/compositor/layer_animation_sequence.cc b/ui/gfx/compositor/layer_animation_sequence.cc
index 8f34969d6801439cc6cc3e639da280662bec38e0..11b00df664ec1330cbe8697c7d5920b55d59e880 100644
--- a/ui/gfx/compositor/layer_animation_sequence.cc
+++ b/ui/gfx/compositor/layer_animation_sequence.cc
@@ -10,6 +10,7 @@
 #include "base/debug/trace_event.h"
 #include "ui/gfx/compositor/layer_animation_delegate.h"
 #include "ui/gfx/compositor/layer_animation_element.h"
+#include "ui/gfx/compositor/layer_animation_observer.h"
 
 namespace ui {
 
@@ -106,4 +107,19 @@ bool LayerAnimationSequence::HasCommonProperty(
   return intersection.size() > 0;
 }
 
+void LayerAnimationSequence::AddObserver(LayerAnimationObserver* observer) {
+  if (!observers_.HasObserver(observer))
+    observers_.AddObserver(observer);
+}
+
+void LayerAnimationSequence::RemoveObserver(LayerAnimationObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void LayerAnimationSequence::NotifyEnded() {
+  FOR_EACH_OBSERVER(LayerAnimationObserver,
+                    observers_,
+                    OnLayerAnimationEnded(this));
+}
+
 }  // namespace ui