Fix notification swipe control button position with RTL UI languages.

Bug: 840497
Test: manually verified
Change-Id: Id853396b9ab2b1ca88df81fa028e0783a8377fe0
Reviewed-on: https://chromium-review.googlesource.com/1201633
Commit-Queue: Tatsuhisa Yamaguchi <yamaguchi@chromium.org>
Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588345}

ui/message_center/views/notification_swipe_control_view.cc

@@ -37,12 +37,11 @@ NotificationSwipeControlView::NotificationSwipeControlView() {
 
 NotificationSwipeControlView::~NotificationSwipeControlView() = default;
 
-void NotificationSwipeControlView::ShowButtons(bool is_right,
+void NotificationSwipeControlView::ShowButtons(ButtonPosition button_position,
                                                bool show_settings,
                                                bool show_snooze) {
   views::BoxLayout* layout = static_cast<views::BoxLayout*>(GetLayoutManager());
-  if (is_right) {
-    // TODO: Flip the arrangement if current UI language is RTL.
+  if ((button_position == ButtonPosition::RIGHT) != base::i18n::IsRTL()) {
     layout->set_main_axis_alignment(views::BoxLayout::MAIN_AXIS_ALIGNMENT_END);
   } else {
     layout->set_main_axis_alignment(

ui/message_center/views/notification_swipe_control_view.h

@@ -28,6 +28,11 @@ class MESSAGE_CENTER_EXPORT NotificationSwipeControlView
     virtual void OnSnoozeButtonPressed(const ui::Event& event) = 0;
   };
 
+  // Physical positions to show buttons in the swipe control. This is invariant
+  // across RTL/LTR languages because buttons should be shown on one side which
+  // is made uncovered by the overlapping view after user's swipe action.
+  enum class ButtonPosition { RIGHT, LEFT };
+
   // String to be returned by GetClassName() method.
   static const char kViewClassName[];
 
@@ -41,7 +46,9 @@ class MESSAGE_CENTER_EXPORT NotificationSwipeControlView
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   // Change the visibility of the settings button.
-  void ShowButtons(bool is_right, bool has_settings, bool has_snooze);
+  void ShowButtons(ButtonPosition button_position,
+                   bool has_settings,
+                   bool has_snooze);
   void HideButtons();
   void AddObserver(Observer* observer);
 

ui/message_center/views/slidable_message_view.cc

@@ -47,12 +47,14 @@ void SlidableMessageView::OnSlideChanged(const std::string& notification_id) {
   if (gesture_amount == 0) {
     control_view_->HideButtons();
   } else {
-    bool on_right = gesture_amount < 0;
+    NotificationSwipeControlView::ButtonPosition button_position =
+        gesture_amount < 0 ? NotificationSwipeControlView::ButtonPosition::RIGHT
+                           : NotificationSwipeControlView::ButtonPosition::LEFT;
     NotificationControlButtonsView* buttons =
         message_view_->GetControlButtonsView();
     bool has_settings_button = buttons->settings_button();
     bool has_snooze_button = buttons->snooze_button();
-    control_view_->ShowButtons(on_right, has_settings_button,
+    control_view_->ShowButtons(button_position, has_settings_button,
                                has_snooze_button);
   }
 }