Introduce AccessibilityFocusRing.

chrome/browser/chromeos/ui/focus_ring_layer.h

Index: chrome/browser/chromeos/ui/focus_ring_layer.h
diff --git a/chrome/browser/chromeos/ui/focus_ring_layer.h b/chrome/browser/chromeos/ui/focus_ring_layer.h
index 478b7cc2ec96a51e23d2589097cae60f336bb011..80021b2b01e0570540e9578c2f3c0ac92af9c0a6 100644
--- a/chrome/browser/chromeos/ui/focus_ring_layer.h
+++ b/chrome/browser/chromeos/ui/focus_ring_layer.h
@@ -39,6 +39,18 @@ class FocusRingLayer : public ui::LayerDelegate {
   // the given root window.
   void Set(aura::Window* root_window, const gfx::Rect& bounds);
 
+ protected:
+  // Updates |root_window_| and creates |layer_| if it doesn't exist,
+  // or if the root window has changed. Moves the layer to the top if
+  // it wasn't there already.
+  void CreateOrUpdateLayer(aura::Window* root_window, const char* layer_name);
+
+  // The current root window containing the focused object.
+  aura::Window* root_window_;

[xiyuan, 2014/09/11 21:56:05]

nit: Can we keep the members in private section and provide an accessors
instead?

[dmazzoni, 2014/09/11 22:14:39]

Done.

+
+  // The current layer.
+  scoped_ptr<ui::Layer> layer_;
+
  private:
   // ui::LayerDelegate overrides:
   virtual void OnPaintLayer(gfx::Canvas* canvas) OVERRIDE;
@@ -50,16 +62,10 @@ class FocusRingLayer : public ui::LayerDelegate {
   // The object that owns this layer.
   FocusRingLayerDelegate* delegate_;
 
-  // The current root window containing the focused object.
-  aura::Window* root_window_;
-
   // The bounding rectangle of the focused object, in |root_window_|
   // coordinates.
   gfx::Rect focus_ring_;
 
-  // The current layer.
-  scoped_ptr<ui::Layer> layer_;
-
   DISALLOW_COPY_AND_ASSIGN(FocusRingLayer);
 };