[FileBrowser] Fixed default hover state.

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

Index: chrome/browser/resources/file_manager/css/common.css
diff --git a/chrome/browser/resources/file_manager/css/common.css b/chrome/browser/resources/file_manager/css/common.css
index 87824d48a70abd2d1a2f22ea0a5d7d3eefac840a..48a3660086ee04f576f952bac05aef7a6e944227 100644
--- a/chrome/browser/resources/file_manager/css/common.css
+++ b/chrome/browser/resources/file_manager/css/common.css
@@ -169,6 +169,20 @@ input.common[type='checkbox']::after {
   z-index: 1;
 }
 
+.buttonbar button:hover {
+  -webkit-transition: all 0;
+  background-image: -webkit-linear-gradient(top, #F8F8F8, #F1F1F1);
+  border: 1px solid #C6C6C6;
+  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.1);
+  color: #222;
+}
+
+.buttonbar button:active {
+  background-color: #F6F6F6;
+  background-image: -webkit-linear-gradient(top,#F6F6F6,#F1F1F1);
+  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
+}
+
 .buttonbar button[disabled] {
   background-color: #EEE;
   background-image: -webkit-linear-gradient(top, #EEE, #E0E0E0);