Fix CSS and timeout handling for the Files app butter bar

chrome/browser/resources/file_manager/main.html

Index: chrome/browser/resources/file_manager/main.html
diff --git a/chrome/browser/resources/file_manager/main.html b/chrome/browser/resources/file_manager/main.html
index d9d1329d4758cd23baeb5f5c12c33b3536a60c8f..72cd1f5f3ef46aeadc39a670b3144b5acc824df2 100644
--- a/chrome/browser/resources/file_manager/main.html
+++ b/chrome/browser/resources/file_manager/main.html
@@ -238,14 +238,14 @@
       </div>
       <button class=cancel i18n-content=CANCEL_LABEL>[CANCEL]</button>
     </div>
-    <div id="butter-bar" class="before-show">
+    <div id="butter-bar">
       <div class="content">
         <div class="butter-message"></div>
-        <div class="progress-bar hide-in-butter">
+        <div class="progress-bar" hidden>
           <div class="progress-track"></div>
         </div>
       </div>
-      <div class="actions hide-in-butter"></div>
+      <div class="actions" hidden></div>
     </div>
     <div id="drag-image-container"></div>
     <iframe id="command-dispatcher" hidden></iframe>