[ash-md] Animates ToggleButton highlight to move it in sync with the thumb

ui/views/controls/button/custom_button_unittest.cc

Index: ui/views/controls/button/custom_button_unittest.cc
diff --git a/ui/views/controls/button/custom_button_unittest.cc b/ui/views/controls/button/custom_button_unittest.cc
index 816d8a4d9cf94ff7d0093da7384349ce4625cea0..418ff6e1c6b28cafad81a4e267f4adb97d239460 100644
--- a/ui/views/controls/button/custom_button_unittest.cc
+++ b/ui/views/controls/button/custom_button_unittest.cc
@@ -22,6 +22,7 @@
 #include "ui/views/controls/button/label_button.h"
 #include "ui/views/controls/button/menu_button.h"
 #include "ui/views/controls/button/radio_button.h"
+#include "ui/views/controls/button/toggle_button.h"
 #include "ui/views/controls/link.h"
 #include "ui/views/controls/textfield/textfield.h"
 #include "ui/views/test/views_test_base.h"
@@ -136,7 +137,7 @@ class CustomButtonTest : public ViewsTestBase {
 
  private:
   std::unique_ptr<Widget> widget_;
-  TestCustomButton* button_;
+  TestCustomButton* button_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(CustomButtonTest);
 };
@@ -335,6 +336,9 @@ TEST_F(CustomButtonTest, AsCustomButton) {
   MenuButton menu_button(text, NULL, false);
   EXPECT_TRUE(CustomButton::AsCustomButton(&menu_button));
 
+  ToggleButton toggle_button(NULL);
+  EXPECT_TRUE(CustomButton::AsCustomButton(&toggle_button));
+
   Label label;
   EXPECT_FALSE(CustomButton::AsCustomButton(&label));