CrOS Shelf: Fix navigation widget position in RTL

Add a test to prevent future regressions.

BUG=991919

Change-Id: I41ebd4f5cee6375f0cb2d510b8d4e91d356a1bc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1761226Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Manu Cornet <manucornet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688293}

ash/shelf/shelf_layout_manager.cc

@@ -1142,8 +1142,10 @@ void ShelfLayoutManager::CalculateTargetBounds(
   gfx::Point nav_origin =
       gfx::Point(ShelfConstants::home_button_edge_spacing(),
                  ShelfConstants::home_button_edge_spacing());
-  target_bounds->nav_bounds_in_shelf =
-      gfx::Rect(nav_origin, shelf_widget_->navigation_widget()->GetIdealSize());
+  const gfx::Size nav_size = shelf_widget_->navigation_widget()->GetIdealSize();
+  if (shelf_->IsHorizontalAlignment() && base::i18n::IsRTL())
+    nav_origin.set_x(shelf_width - nav_size.width() - nav_origin.x());
+  target_bounds->nav_bounds_in_shelf = gfx::Rect(nav_origin, nav_size);
 
   gfx::Point hotseat_origin;
   int hotseat_width;

ash/shelf/shelf_layout_manager_unittest.cc

@@ -56,6 +56,7 @@
 #include "ash/wm/workspace_controller.h"
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/i18n/rtl.h"
 #include "base/run_loop.h"
 #include "base/stl_util.h"
 #include "base/test/metrics/user_action_tester.h"
@@ -3058,6 +3059,34 @@ TEST_F(ShelfLayoutManagerTest, AutoHideShelfHiddenForSinglePipWindow) {
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->GetAutoHideState());
 }
 
+// Verifies that shelf components are placed properly in right-to-left UI.
+TEST_F(ShelfLayoutManagerTest, RtlPlacement) {
+  // Helper function to check that the given widget is placed symmetrically
+  // between LTR and RTL.
+  auto check_mirrored_placement = [](views::Widget* widget) {
+    base::i18n::SetICUDefaultLocale("en");
+    EXPECT_FALSE(base::i18n::IsRTL());
+    GetShelfLayoutManager()->LayoutShelf();
+    const int ltr_left_position =
+        widget->GetNativeWindow()->GetBoundsInScreen().x();
+
+    base::i18n::SetICUDefaultLocale("ar");
+    EXPECT_TRUE(base::i18n::IsRTL());
+    GetShelfLayoutManager()->LayoutShelf();
+    const int rtl_right_position =
+        widget->GetNativeWindow()->GetBoundsInScreen().right();
+
+    EXPECT_EQ(
+        GetShelfWidget()->GetWindowBoundsInScreen().width() - ltr_left_position,
+        rtl_right_position);
+  };
+
+  ShelfWidget* shelf_widget = GetPrimaryShelf()->shelf_widget();
+  check_mirrored_placement(shelf_widget->navigation_widget());
+  check_mirrored_placement(shelf_widget->status_area_widget());
+  check_mirrored_placement(shelf_widget);
+}
+
 class ShelfLayoutManagerKeyboardTest : public AshTestBase {
  public:
   ShelfLayoutManagerKeyboardTest() = default;