Perf: remove unnecessary shadows and mask views

App/Browser View/BrowserView.swift

@@ -149,6 +149,10 @@ class BrowserView: UIView
                 autocompleteView.layer.cornerRadius = 8.0
                 autocompleteView.layer.masksToBounds = true
                 
+                let shadowPath = UIBezierPath(roundedRect: autocompleteView.bounds,
+                                              cornerRadius: autocompleteView.layer.cornerRadius)
+                autocompleteView.layer.shadowPath = shadowPath.cgPath
+                
                 if let toolbarView = toolbarView, let urlBar = toolbarView.urlBar {
                     let urlFrame = self.convert(urlBar.frame, from: urlBar.superview)
                     autocompleteView.frame = CGRect(
@@ -158,6 +162,9 @@ class BrowserView: UIView
                         height: bounds.height / 2.5
                     )
                 }
+            } else {
+                autocompleteView.layer.cornerRadius = 0.0
+                autocompleteView.layer.shadowOpacity = 0.0
             }
         }