Wallpaper's layer do not have to be translucent.

This was added in [1] to deal with the login web page. I believe
this is no longer relevant.

[1] https://chromiumcodereview.appspot.com/10454017

Bug: None
Test: login/oobe screen works as is.
Change-Id: Ib6275fe7a4c934797631e00c1c4a29ed650b5502
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2062672Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742320}

ash/wallpaper/wallpaper_view.cc

@@ -215,8 +215,6 @@ std::unique_ptr<views::Widget> CreateWallpaperWidget(
   params.name = "WallpaperViewWidget";
   params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   params.layer_type = ui::LAYER_NOT_DRAWN;
-  if (controller->GetWallpaper().isNull())
-    params.opacity = views::Widget::InitParams::WindowOpacity::kTranslucent;
   params.parent = root_window->GetChildById(container_id);
   WallpaperView* wallpaper_view = new WallpaperView(property);
   params.delegate = new WallpaperWidgetDelegate(wallpaper_view);