CrOS App List: Fix app list corners to be rounded when shelf is rounded

Bug: 1042474
Change-Id: I6b2f2fa280b6739819fc7e8f4fb266f1e7bb9453
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003616
Commit-Queue: Matthew Mourgos <mmourgos@chromium.org>
Reviewed-by: Manu Cornet <manucornet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734712}

ash/shelf/shelf_layout_manager.cc

@@ -795,8 +795,11 @@ ShelfBackgroundType ShelfLayoutManager::GetShelfBackgroundType() const {
       return ShelfBackgroundType::kInApp;
     }
   } else if (app_list_is_visible) {
-    return maximized ? ShelfBackgroundType::kMaximizedWithAppList
-                     : ShelfBackgroundType::kAppList;
+    // When auto-hide shelf is enabled, shelf cannot be considered maximized.
+    if (maximized && state_.visibility_state != SHELF_AUTO_HIDE)
+      return ShelfBackgroundType::kMaximizedWithAppList;
+
+    return ShelfBackgroundType::kAppList;
   }
 
   if (maximized) {