Video Player: Not hide the video control bar on error

The cast icon has moved to the video control bar, so we should keep it visible even on error.

BUG=419651
TEST=manual

Review URL: https://codereview.chromium.org/620803002

Cr-Commit-Position: refs/heads/master@{#297787}

ui/file_manager/video_player/css/video_player.css

@@ -139,11 +139,6 @@ video {
   cursor: none;
 }
 
-/* Hides controls when disabled mode */
-#video-player[disabled] > #controls-wrapper .tool {
-  display: none;
-}
-
 .tool {
   transition: opacity 180ms linear;
 }