Add ripple effect to action in expand button.

ui/message_center/views/notification_view_md.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/message_center/views/notification_view_md.h"
 
 #include <stddef.h>
 
 #include "base/strings/string_util.h"
 #include "ui/base/cursor/cursor.h"
@@ skipping 471 matching lines @@
   }
 
   if (header_row_->IsSettingsButtonEnabled() &&
       sender == header_row_->settings_button()) {
     controller()->ClickOnSettingsButton(id);
     return;
   }
 
   // Tapping anywhere on |header_row_| can expand the notification, though only
   // |expand_button| can be focused by TAB.
-  if (IsExpandable() &&
-      (sender == header_row_ || sender == header_row_->expand_button())) {
+  if (IsExpandable() && sender == header_row_) {
     ToggleExpanded();
     Layout();
     SchedulePaint();
     return;
   }
 
   // See if the button pressed was an action button.
   for (size_t i = 0; i < action_buttons_.size(); ++i) {
     if (sender == action_buttons_[i]) {
       controller()->ClickOnNotificationButton(id, i);
@@ skipping 322 matching lines @@
                                   header_row_->expand_button()->HasFocus()) ||
                                  (header_row_->IsCloseButtonEnabled() &&
                                   header_row_->close_button()->HasFocus()) ||
                                  (header_row_->IsSettingsButtonEnabled() &&
                                   header_row_->settings_button()->HasFocus());
 
   header_row_->SetControlButtonsVisible(target_visibility);
 }
 
 }  // namespace message_center