shelf: Do not blur animating background

The animating background is shown during hotseat animation, and might
cause double blur (for example, navigation control, or hotseat blur
might be active at the same time).

BUG=1034045

Change-Id: I9ef8e06cdcd2b9662ba91eb4728ac4f1cef4f19a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1986328Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: Manu Cornet <manucornet@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728121}

ash/shelf/shelf_widget.cc

@@ -189,11 +189,8 @@ ShelfWidget::DelegateView::DelegateView(ShelfWidget* shelf_widget)
 
   // |animating_background_| will be made visible during hotseat animations.
   ShowAnimatingBackground(false);
-  if (features::IsBackgroundBlurEnabled()) {
-    animating_background_.SetBackdropFilterQuality(0.33f);
-    animating_background_.SetColor(
-        ShelfConfig::Get()->GetMaximizedShelfColor());
-  }
+  animating_background_.SetColor(ShelfConfig::Get()->GetMaximizedShelfColor());
+
   std::unique_ptr<views::View> drag_handle_ptr =
       std::make_unique<views::View>();
   const int radius = kDragHandleCornerRadius;
@@ -406,11 +403,6 @@ void ShelfWidget::DelegateView::OnHotseatTransitionAnimationEnded(
 
 void ShelfWidget::DelegateView::ShowAnimatingBackground(bool show) {
   animating_background_.SetVisible(show);
-
-  // To ensure smooth scrollable shelf animations, we disable blur when the
-  // |animating_background_| is not visible.
-  if (features::IsBackgroundBlurEnabled())
-    animating_background_.SetBackgroundBlur(show ? 30 : 0);
 }
 
 SkColor ShelfWidget::DelegateView::GetShelfBackgroundColor() const {