Move MdFocusRing to be a property of FocusManager.

ui/views/focus/focus_manager.h

Index: ui/views/focus/focus_manager.h
diff --git a/ui/views/focus/focus_manager.h b/ui/views/focus/focus_manager.h
index 99ca6e6772662baf0446feffbe3bf6e705ba6e19..051d7098cb6ad62e2b6010a59fb7a93c07f2cf34 100644
--- a/ui/views/focus/focus_manager.h
+++ b/ui/views/focus/focus_manager.h
@@ -83,6 +83,10 @@ class KeyEvent;
 
 namespace views {
 
+namespace internal {
+class MdFocusRing;
+}
+
 class FocusManagerDelegate;
 class FocusSearch;
 class View;
@@ -384,6 +388,9 @@ class VIEWS_EXPORT FocusManager {
   // Default value is false.
   bool keyboard_accessible_;
 
+  // See class-level comment for MdFocusRing.
+  std::unique_ptr<internal::MdFocusRing> focus_ring_;
+
   DISALLOW_COPY_AND_ASSIGN(FocusManager);
 };