Focus following for the non-editable controls on web page in magnifier mode.

ash/magnifier/magnification_controller.h

Index: ash/magnifier/magnification_controller.h
diff --git a/ash/magnifier/magnification_controller.h b/ash/magnifier/magnification_controller.h
index e85449169d28e988664c8a4f67e2d46a9efdb0c7..93b1805812d11de22bed2a3f7a5fa42665b67ee4 100644
--- a/ash/magnifier/magnification_controller.h
+++ b/ash/magnifier/magnification_controller.h
@@ -53,6 +53,16 @@ class ASH_EXPORT MagnificationController {
 
   virtual void SetScrollDirection(ScrollDirection direction) = 0;
 
+  // Returns the view port(i.e. the current visible window)'s Rect in root
+  // window coordinates.
+  virtual gfx::Rect GetViewportRect() = 0;
+
+  // Handles focusedNodeChanged event, follows the focus on web page for
+  // non-editable controls.
+  virtual void HandleFocusedNodeChanged(
+      bool is_editable_node,
+      const gfx::Rect& node_bounds_in_screen) = 0;
+
   // Returns |point_of_interest_| in MagnificationControllerImpl. This is
   // the internal variable to stores the last mouse cursor (or last touched)
   // location. This method is only for test purpose.