Update some example + test code to use MdTextButton instead of

ui/views/focus/focus_manager_unittest.cc

Index: ui/views/focus/focus_manager_unittest.cc
diff --git a/ui/views/focus/focus_manager_unittest.cc b/ui/views/focus/focus_manager_unittest.cc
index da6ededa69ea0a29dd463aa63f86be06f13dec08..a655eafcc45e0c3d37abf43989a3f78704fc6db0 100644
--- a/ui/views/focus/focus_manager_unittest.cc
+++ b/ui/views/focus/focus_manager_unittest.cc
@@ -15,7 +15,6 @@
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/views/accessible_pane_view.h"
-#include "ui/views/controls/button/label_button.h"
 #include "ui/views/focus/focus_manager_factory.h"
 #include "ui/views/focus/widget_focus_manager.h"
 #include "ui/views/test/focus_manager_test.h"
@@ -482,21 +481,6 @@ class FocusManagerDtorTest : public FocusManagerTest {
     DISALLOW_COPY_AND_ASSIGN(TestFocusManagerFactory);
   };
 
-  class LabelButtonDtorTracked : public LabelButton {
-   public:
-    LabelButtonDtorTracked(const base::string16& text,
-                           DtorTrackVector* dtor_tracker)
-        : LabelButton(NULL, text),
-          dtor_tracker_(dtor_tracker) {
-      SetStyle(STYLE_BUTTON);
-    };
-    ~LabelButtonDtorTracked() override {
-      dtor_tracker_->push_back("LabelButtonDtorTracked");
-    }
-
-    DtorTrackVector* dtor_tracker_;
-  };
-
   class WindowDtorTracked : public Widget {
    public:
     explicit WindowDtorTracked(DtorTrackVector* dtor_tracker)