Use in-screen bounds when setting up hotseat transition

BUG=1161552

Change-Id: Ib8b88d088c16178c0ffb2c34bdd747abc2354ad3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2607653Reviewed-by: Andrew Xu <andrewxu@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839921}

ash/shelf/hotseat_widget.cc

@@ -1134,7 +1134,7 @@ void HotseatWidget::LayoutHotseatByAnimation(double target_opacity,
   // between hidden and extended state use transform to animate. Clear any
   // transform that may have been set by the previous animation, and update
   // current bounds to match it.
-  gfx::RectF current_bounds_f(hotseat_layer->bounds());
+  gfx::RectF current_bounds_f(GetNativeView()->GetBoundsInScreen());
   hotseat_layer->transform().TransformRect(&current_bounds_f);
   gfx::Rect current_bounds = gfx::ToEnclosingRect(current_bounds_f);