Revert of [M55] Generalize layer mirroring for phantom windows

ui/compositor/layer.h

Index: ui/compositor/layer.h
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index e882bbb5f42a7f43a6bcf26bb0e89780a5c14576..7c7e4e32562c1899c69a438587c10cc6aaeafea6 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -76,16 +76,6 @@
   explicit Layer(LayerType type);
   ~Layer() override;
 
-  // Note that only solid color and surface content is copied.
-  std::unique_ptr<Layer> Clone() const;
-
-  // Returns a new layer that mirrors this layer and is optionally synchronized
-  // with the bounds thereof. Note that children are not mirrored, and that the
-  // content is only mirrored if painted by a delegate or backed by a surface.
-  std::unique_ptr<Layer> Mirror();
-
-  void set_sync_bounds(bool sync_bounds) { sync_bounds_ = sync_bounds; }
-
   // Retrieves the Layer's compositor. The Layer will walk up its parent chain
   // to locate it. Returns NULL if the Layer is not attached to a compositor.
   Compositor* GetCompositor() {
@@ -313,7 +303,7 @@
 
   // Sets the layer's fill color.  May only be called for LAYER_SOLID_COLOR.
   void SetColor(SkColor color);
-  SkColor GetTargetColor() const;
+  SkColor GetTargetColor();
   SkColor background_color() const;
 
   // Updates the nine patch layer's image, aperture and border. May only be
@@ -393,7 +383,6 @@
 
  private:
   friend class LayerOwner;
-  class LayerMirror;
 
   void CollectAnimators(std::vector<scoped_refptr<LayerAnimator> >* animators);
 
@@ -444,8 +433,6 @@
   void SetCompositorForAnimatorsInTree(Compositor* compositor);
   void ResetCompositorForAnimatorsInTree(Compositor* compositor);
 
-  void OnMirrorDestroyed(LayerMirror* mirror);
-
   const LayerType type_;
 
   Compositor* compositor_;
@@ -454,11 +441,6 @@
 
   // This layer's children, in bottom-to-top stacking order.
   std::vector<Layer*> children_;
-
-  std::vector<std::unique_ptr<LayerMirror>> mirrors_;
-
-  // If true, changes to the bounds of this layer are propagated to mirrors.
-  bool sync_bounds_ = false;
 
   gfx::Rect bounds_;
   gfx::Vector2dF subpixel_position_offset_;