Video Player: Adds hover state cast icons

ui/file_manager/video_player/css/header.css

Index: ui/file_manager/video_player/css/header.css
diff --git a/ui/file_manager/video_player/css/header.css b/ui/file_manager/video_player/css/header.css
index 35868372fc8d71154a47bf041c46aa6fc2d71b80..591cf84154db13d1422fa3aff09cff8c82176e41 100644
--- a/ui/file_manager/video_player/css/header.css
+++ b/ui/file_manager/video_player/css/header.css
@@ -81,6 +81,18 @@
       url(../images/200/cast_on.png) 2x);
 }
 
+#video-player > .header > button.cast-button:hover {
+  background-image: -webkit-image-set(
+      url(../images/100/cast_off_hover.png) 1x,
+      url(../images/200/cast_off_hover.png) 2x);
+}
+
+#video-player[casting] > .header > button.cast-button:hover {
+  background-image: -webkit-image-set(
+      url(../images/100/cast_on_hover.png) 1x,
+      url(../images/200/cast_on_hover.png) 2x);
+}
+
 #video-player > .header > button.cast-button {
   display: none;
 }