CC Animations: Make LayerAnimationController creation optional

ui/compositor/layer.h

Index: ui/compositor/layer.h
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index 3dbd1733b0b2982eacc194383e25f1dcc12a441e..ee279c7150942e8a8a33ddbae1b5fb53e44da13e 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -88,6 +88,8 @@ class COMPOSITOR_EXPORT Layer
   // Called by the compositor when the Layer is set as its root Layer. This can
   // only ever be called on the root layer.
   void SetCompositor(Compositor* compositor);
+  void SetCompositorRootLayer(scoped_refptr<cc::Layer> root_layer);

[ajuma, 2015/04/24 16:02:16]

SetCompositorRootCCLayer maybe? (so the difference between this and
SetCompositor is clearer)

[loyso (OOO), 2015/04/27 06:34:08]

Done.

+  void ResetCompositor();
 
   LayerDelegate* delegate() { return delegate_; }
   void set_delegate(LayerDelegate* delegate) { delegate_ = delegate; }
@@ -140,6 +142,8 @@ class COMPOSITOR_EXPORT Layer
   void SetTransform(const gfx::Transform& transform);
   gfx::Transform transform() const;
 
+  gfx::PointF position() const { return cc_layer_->position(); }
+
   // Return the target transform if animator is running, or the current
   // transform otherwise.
   gfx::Transform GetTargetTransform() const;
@@ -347,7 +351,7 @@ class COMPOSITOR_EXPORT Layer
       ContentLayerClient::PaintingControlSetting painting_control) override;
   bool FillsBoundsCompletely() const override;
 
-  cc::Layer* cc_layer() { return cc_layer_; }
+  cc::Layer* cc_layer_for_testing() { return cc_layer_; }
 
   // TextureLayerClient
   bool PrepareTextureMailbox(
@@ -413,6 +417,10 @@ class COMPOSITOR_EXPORT Layer
   // Creates a corresponding composited layer for |type_|.
   void CreateCcLayer();
 
+  // Attach/Detach CC Layer animation event observers.
+  void AttachAnimationObservers();
+  void DetachAnimationObservers();
+
   // Recomputes and sets to |cc_layer_|.
   void RecomputeDrawsContentAndUVRect();
   void RecomputePosition();