From Cedric Pinson, The following modification are

Update Timeline.cpp to add current layer to the ActionVisitor, use correctly the priority
Add accessors in Action.cpp to retrieve protected data
Split files and rename them to classname
Change de default color of UpdateMaterial to FFOOFF to detect unset value
Add accessors in LinkVisitor instead of accessing data directly
Update osganimationtimeline example to fit the api callback

include/osgAnimation/Action

@@ -166,7 +166,7 @@ namespace osgAnimation
         ActionAnimation() {}
         ActionAnimation(const ActionAnimation& a, const osg::CopyOp& c) : Action(a,c) { _animation = a._animation;}
         ActionAnimation(Animation* animation);
-        void updateAnimation(unsigned int frame);
+        void updateAnimation(unsigned int frame, int priority);
         Animation* getAnimation() { return _animation.get(); }
 
     protected:
@@ -192,8 +192,6 @@ namespace osgAnimation
         
         unsigned int getLoop() const { return _animation->getLoop(); }
         void setLoop(unsigned int loop);
-        void computeWeightAndUpdateAnimation(unsigned int frame);
-
         void traverse(ActionVisitor& visitor);
 
     protected: