Add spacing between holding space bubble and shelf

Bug: 1129698
Change-Id: I9a2fc1128ac069f40ce42e1ae4c597a8ee26c581
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417493Reviewed-by: David Black <dmblack@google.com>
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808227}

ash/system/holding_space/holding_space_tray.cc

@@ -137,7 +137,6 @@ void HoldingSpaceTray::ShowBubble(bool show_by_click) {
   init_params.delegate = this;
   init_params.parent_window = GetBubbleWindowContainer();
   init_params.anchor_view = GetBubbleAnchor();
-  init_params.insets = GetTrayBubbleInsets();
   init_params.shelf_alignment = shelf()->alignment();
   init_params.preferred_width = kHoldingSpaceWidth;
   init_params.close_on_deactivate = true;
@@ -147,6 +146,7 @@ void HoldingSpaceTray::ShowBubble(bool show_by_click) {
   // Create and customize bubble view.
   TrayBubbleView* bubble_view = new TrayBubbleView(init_params);
   bubble_view->set_anchor_view_insets(GetBubbleAnchorInsets());
+  bubble_view->set_margins(GetSecondaryBubbleInsets());
 
   // Add pinned files container.
   pinned_files_container_ =