Extensions: fix focus being chopped in pack dialog.

Bug: 854936
Cq-Include-Trybots: luci.chromium.try:closure_compilation
Change-Id: Id5e2f544cf2425e641c68d042b88b40230ba471c
Reviewed-on: https://chromium-review.googlesource.com/1110856Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Scott Chen <scottchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569689}

chrome/browser/resources/md_extensions/pack_dialog.html

@@ -22,6 +22,12 @@
       paper-button[slot='suffix'] {
         -webkit-margin-start: 10px;
       }
+
+      /* Prevent focus-outline from being chopped by the bottom of dialog body.
+         TODO(scottchen): find a more general way to solve this. */
+      cr-input {
+        margin-bottom: 2px;
+      }
     </style>
     <cr-dialog id="dialog" close-text="$i18n{close}">
       <div slot="title">$i18n{packDialogTitle}</div>