Fix hotseat bounds under RTL

This CL fixes two things:
(1) We use a solid-color layer to draw hotseat background. However,
Layer::SetBounds() does not mirror bounds under RTL. So we should do
it manually.
(2) View::SetBounds() mirrors bounds under RTL. So mirroring bounds
manually in ShelfView's member function is unnecessary.

Bug: 1094026
Change-Id: Iab5564b6687d7279733e5aa6d37fe41ef28cd15f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2261421Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Andrew Xu <andrewxu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781544}

ash/shelf/hotseat_widget.cc

@@ -389,8 +389,10 @@ void HotseatWidget::DelegateView::UpdateTranslucentBackground() {
     return;
   }
 
-  SetTranslucentBackground(
-      scrollable_shelf_view_->GetHotseatBackgroundBounds());
+  // Layer::SetBounds() does not mirror bounds under RTL. So set the mirrored
+  // bounds explicitly.
+  SetTranslucentBackground(scrollable_shelf_view_->GetMirroredRect(
+      scrollable_shelf_view_->GetHotseatBackgroundBounds()));
 }
 
 void HotseatWidget::DelegateView::SetTranslucentBackground(
@@ -646,9 +648,8 @@ float HotseatWidget::CalculateShelfViewOpacity() const {
   return (state() == HotseatState::kExtended) ? 1.0f : target_opacity;
 }
 
-void HotseatWidget::SetTranslucentBackground(
-    const gfx::Rect& translucent_background_bounds) {
-  delegate_view_->SetTranslucentBackground(translucent_background_bounds);
+void HotseatWidget::UpdateTranslucentBackground() {
+  delegate_view_->UpdateTranslucentBackground();
 }
 
 int HotseatWidget::CalculateHotseatYInScreen(

ash/shelf/hotseat_widget.h

@@ -96,9 +96,9 @@ class ASH_EXPORT HotseatWidget : public ShelfComponent,
   // Returns the target opacity for the shelf view given current conditions.
   float CalculateShelfViewOpacity() const;
 
-  // Sets the bounds of the translucent background which functions as the
+  // Updates the bounds of the translucent background which functions as the
   // hotseat background.
-  void SetTranslucentBackground(const gfx::Rect& background_bounds);
+  void UpdateTranslucentBackground();
 
   // Calculates the hotseat y position for |hotseat_target_state| in screen
   // coordinates.

ash/shelf/scrollable_shelf_view.cc

@@ -2081,10 +2081,8 @@ void ScrollableShelfView::UpdateAvailableSpace() {
 
   // The hotseat uses |available_space_| to determine where to show its
   // background, so notify it when it is recalculated.
-  if (HotseatWidget::ShouldShowHotseatBackground()) {
-    GetShelf()->hotseat_widget()->SetTranslucentBackground(
-        GetHotseatBackgroundBounds());
-  }
+  if (HotseatWidget::ShouldShowHotseatBackground())
+    GetShelf()->hotseat_widget()->UpdateTranslucentBackground();
 }
 
 gfx::Rect ScrollableShelfView::CalculateVisibleSpace(

ash/shelf/shelf_view.cc

@@ -2281,14 +2281,7 @@ int ShelfView::CalculateAppIconsLayoutOffset() const {
   const gfx::Insets& edge_padding_insets =
       scrollable_shelf_view->edge_padding_insets();
 
-  // Paddings are within the shelf view. It makes sure that |shelf_view_|'s
-  // bounds are not changed by adding/removing the shelf icon under the same
-  // layout strategy.
-  const int horizontal_inset = scrollable_shelf_view->ShouldAdaptToRTL()
-                                   ? edge_padding_insets.right()
-                                   : edge_padding_insets.left();
-
-  return shelf_->IsHorizontalAlignment() ? horizontal_inset
+  return shelf_->IsHorizontalAlignment() ? edge_padding_insets.left()
                                          : edge_padding_insets.top();
 }