[CrOS] Fix public account arrow button size on login screen

Bug: 1158825
Change-Id: I740a162a81768fa2cc7271315b553070636757fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2592800
Commit-Queue: Thomas Tellier <tellier@google.com>
Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837550}

ash/login/ui/login_public_account_user_view.cc

@@ -93,7 +93,17 @@ LoginPublicAccountUserView::LoginPublicAccountUserView(
   add_padding(kDistanceFromTopOfBigUserViewToUserIconDp);
   AddChildView(std::move(wrapped_user_view));
   add_padding(kDistanceFromUserViewToArrowButton);
-  arrow_button_ = AddChildView(std::move(arrow_button));
+
+  // Arrow button size should be its preferred size so we wrap it.
+  auto* arrow_button_container =
+      AddChildView(std::make_unique<NonAccessibleView>());
+  auto container_layout = std::make_unique<views::BoxLayout>(
+      views::BoxLayout::Orientation::kHorizontal);
+  container_layout->set_main_axis_alignment(
+      views::BoxLayout::MainAxisAlignment::kCenter);
+  arrow_button_container->SetLayoutManager(std::move(container_layout));
+  arrow_button_ = arrow_button_container->AddChildView(std::move(arrow_button));
+
   add_padding(kDistanceFromArrowButtonToBigUserViewBottom);
 
   // Update authentication UI.

ash/login/ui/login_public_account_user_view_unittest.cc

@@ -174,29 +174,36 @@ TEST_F(LoginPublicAccountUserViewTest, ArrowButtonDoesNotChangeViewBounds) {
       public_account_view_->GetBoundsInScreen();
   EXPECT_NE(auth_disabled_bounds, gfx::Rect());
 
+  auto* arrow_button = public_account_test.arrow_button();
   // Move mouse over the view, the arrow button becomes opaque.
   // View bounds should not change.
   GetEventGenerator()->MoveMouseTo(
       public_account_view_->user_view()->GetBoundsInScreen().CenterPoint());
-  EXPECT_EQ(public_account_test.arrow_button()->layer()->opacity(), 1);
+  EXPECT_EQ(arrow_button->layer()->opacity(), 1);
   EXPECT_EQ(public_account_view_->GetBoundsInScreen(), auth_disabled_bounds);
-  EXPECT_EQ(public_account_view_->GetBoundsInScreen().x(),
-            public_account_test.arrow_button()->GetBoundsInScreen().x());
+  int arrow_left_margin = arrow_button->GetBoundsInScreen().x();
+  int arrow_right_margin = public_account_view_->GetBoundsInScreen().width() -
+                           arrow_button->GetBoundsInScreen().x() -
+                           arrow_button->GetBoundsInScreen().width();
+  EXPECT_NEAR(arrow_left_margin, arrow_right_margin, 1);
 
   // Move out the view makes it non-opaque. View bounds should stay the same.
   GetEventGenerator()->MoveMouseTo(
       focusable_view_->GetBoundsInScreen().CenterPoint());
-  EXPECT_EQ(public_account_test.arrow_button()->layer()->opacity(), 0);
+  EXPECT_EQ(arrow_button->layer()->opacity(), 0);
   EXPECT_EQ(public_account_view_->GetBoundsInScreen(), auth_disabled_bounds);
 
   // Set auth enable forces arrow button to be opaque.
   // View bounds should not change.
   public_account_view_->SetAuthEnabled(true /*enabled*/, false /*animate*/);
   EXPECT_TRUE(public_account_view_->auth_enabled());
-  EXPECT_EQ(public_account_test.arrow_button()->layer()->opacity(), 1);
+  EXPECT_EQ(arrow_button->layer()->opacity(), 1);
   EXPECT_EQ(public_account_view_->GetBoundsInScreen(), auth_disabled_bounds);
-  EXPECT_EQ(public_account_view_->GetBoundsInScreen().x(),
-            public_account_test.arrow_button()->GetBoundsInScreen().x());
+  arrow_left_margin = arrow_button->GetBoundsInScreen().x();
+  arrow_right_margin = public_account_view_->GetBoundsInScreen().width() -
+                       arrow_button->GetBoundsInScreen().x() -
+                       arrow_button->GetBoundsInScreen().width();
+  EXPECT_NEAR(arrow_left_margin, arrow_right_margin, 1);
 }
 
 }  // namespace ash