[File Manager] Hide hover state when using keyboard.

chrome/browser/resources/file_manager/css/file_manager.css

Index: chrome/browser/resources/file_manager/css/file_manager.css
diff --git a/chrome/browser/resources/file_manager/css/file_manager.css b/chrome/browser/resources/file_manager/css/file_manager.css
index 5644f471090e4300452081908bc7018a872a659c..16dd7f980146673b8b5a6e9f85cf9316c26fc911 100644
--- a/chrome/browser/resources/file_manager/css/file_manager.css
+++ b/chrome/browser/resources/file_manager/css/file_manager.css
@@ -647,6 +647,12 @@ div.img-container > img {
   border-color: rgb(242, 246, 250);
 }
 
+.list-container.nohover list > :not([selected]):hover,
+.list-container.nohover grid > :not([selected]):hover {
+  background-color: transparent;
+  border-color: transparent;
+}
+
 .table-row-cell .filename-label,
 .thumbnail-item .filename-label,
 /* Show ellipsis in cells. The name column has different structure and overrides