Minor code cleanup

Remove unnecesary call to set background distance.

Bug: none
Change-Id: I2060a7c3b2d239ca7e03fb30ca5995b706452ece
Reviewed-on: https://chromium-review.googlesource.com/742163Reviewed-by: Christopher Grant <cjgrant@chromium.org>
Commit-Queue: Biao She <bshe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512524}

chrome/browser/vr/ui_scene_manager.cc

@@ -914,8 +914,6 @@ void UiSceneManager::ConfigureScene() {
         -kCloseButtonDistance);
     close_button_->SetSize(kCloseButtonWidth, kCloseButtonHeight);
   }
-  scene_->set_background_distance(kContentDistance *
-                                  kBackgroundDistanceMultiplier);
 
   scene_->root_element().SetMode(mode());